View Full Version : Most Reliable AR15 for Self Defense?
SouthwestAviator
01-04-19, 20:45
I've been deliberating over this issue for months. I bought a Colt 6920 as my main go-to rifle in 2016 specifically because I thought it was the most reliable AR15 I could buy. It has never jammed, but several months ago I started reading about the improved reliability of midlength gas systems and am doubting my purchase. In short, I want the most reliable AR15 I can get. I'm not interested in the bells and whistles of the KAC or URGI, but I am interested in maximum reliability. I'd rather not have to spend $2500 on just the rifle and would prefer something basic, but I will save up for that if that's what it takes.
What is the most reliable AR15? Do you have to go to KAC with the expensive features I don't want (such as the URX rail, flash hider, etc) to get the most reliable rifle?
(I also have a Colt AR15A4, but I'm starting to agree that it's a bit long for indoors use)
Something I've been considering was re-barreling my 6920 with the same barrel the URGI uses by Daniel Defense, but I'm not sure if that's an efficient option.
You really don't need to start a new thread everytime a new idea comes to light. You are overthinking this shit massively. Get your carbine set up, and spend some money on reputable training first.
I've been deliberating over this issue for months. I bought a Colt 6920 as my main go-to rifle in 2016 specifically because I thought it was the most reliable AR15 I could buy. It has never jammed, but several months ago I started reading about the improved reliability of midlength gas systems and am doubting my purchase. In short, I want the most reliable AR15 I can get. I'm not interested in the bells and whistles of the KAC or URGI, but I am interested in maximum reliability. I'd rather not have to spend $2500 on just the rifle and would prefer something basic, but I will save up for that if that's what it takes.
What is the most reliable AR15? Do you have to go to KAC with the expensive features I don't want (such as the URX rail, flash hider, etc) to get the most reliable rifle?
(I also have a Colt AR15A4, but I'm starting to agree that it's a bit long for indoors use)
Something I've been considering was re-barreling my 6920 with the same barrel the URGI uses by Daniel Defense, but I'm not sure if that's an efficient option.
SouthwestAviator
01-04-19, 20:59
I understand if this thread needs to be taken down or locked. I'm aware I've been talking about it quite a bit. I guess I'm just still just experiencing buyers remorse.
You bought a reliable rifle. Things can and will break with use (KAC too). Rest easy. Shoot it and have fun.
This is obsessive in the extreme.
Buy a good rifle. Use good ammo, and good mags.
Practice, if you have an issue, fix it.
Colt it a great choice.
KAC is a great choice.
Bcm or DD midlengths are great choices.
You could buy a mod1 KAC upper for a bit less and throw it on your colt lower to save some money.
Hammer_Man
01-04-19, 21:21
I doubt you will ever break your 6920, or shoot enough to wear it out. Buy ammo, mags, a decent optic, and train with it. There is nothing inherently unreliable about a carbine gas system, especially on a rifle made by a reputable manufacturer like Colt, DD, BCM, etc..
A number of AR's are very reliable, a Colt 6920 is one of them. If your weapon malfunctions in combat, it doesn't guarantee that you are dead. Immediate action, spare mags and the ability to remain calm under fire will probably prevail. If it don't, maximum reliability probably wouldn't save you from being dead. I can't swear to this, but I think most dead people would still be dead with an absolutely flawless AR and lots of people are still alive, in spite of the fact they had to use a shitty AR.
Edited because there is nothing I can add to what the SMEs are telling you. Your 6920 is the Toyota Tacoma or the Honda Civic of the AR world, never a bad choice.
Andy
echo5whiskey
01-04-19, 21:53
No failure=no problem.
Every manufacturer will have its odd goof-up. Most "bottom-barrel" manufacturers will have their exceptionally well-built flukes. Everyone has an opinion on what the best is, but "if it ain't broke, don't fix it."
Like Iraqguns said, worry more about getting good training on it. If it does eventually fail, figure out the problem; and go from there. Don't buy into the "this is the best that ever was" stuff, because it's usually nothing more than anecdotal drivel in favor of someone's opinion.
Now, that doesn't mean that if a company has a reputation for poor QC or materials, that you should chance it; but a solid gun plus great training is better than a top-of-the-line masterpiece with none...unless, of course you have the means to get both. :p
SouthwestAviator
01-04-19, 22:08
Alright, I appreciate everyone's responses. For now I'm going to buy more ammo, a red dot, practice, and attend another training class. I won't beat this dead horse anymore. Eventually I may spring for a midlength upper.
Now that you've owned it for two years with no malfunctions, anything you change has the potential to introduce new unforeseen problems.
If I had this level of OCD, I would just buy an LMT Enhanced BCG, shoot it 500 rounds, and if no malfunctions call it a day.
Do you have an Aimpoint Micro/Comp or a Trijicon ACOG as your optic? Do you have a Surefire M300 or m600 Scout light? Those are the standards for reliability in optics and lights.
How about mags? OKAY Surefeed E2 are the most reliable feeding mags for home defense. In the field, they can bend and dent so it's Pmags and Lancers for that application.
How about ammo? You need super reliable ammo that works with your gun.
If you do want a mid length system, pick up a BCM mid-length with their MCMR rail and ELW BFH barrel. Either just the upper, or upper and lower separately to save on the 11% excise tax. You'll get the free float rail, properly contoured barrel, and BCM qc.
SouthwestAviator
01-04-19, 22:39
Now that you've owned it for two years with no malfunctions, anything you change has the potential to introduce new unforeseen problems.
If I had this level of OCD, I would just buy an LMT Enhanced BCG, shoot it 500 rounds, and if no malfunctions call it a day.
Do you have an Aimpoint Micro/Comp or a Trijicon ACOG as your optic? Do you have a Surefire M300 or m600 Scout light? Those are the standards for reliability in optics and lights.
How about mags? OKAY Surefeed E2 are the most reliable feeding mags for home defense. In the field, they can bend and dent so it's Pmags and Lancers for that application.
How about ammo? You need super reliable ammo that works with your gun.
If you do want a mid length system, pick up a BCM mid-length with their MCMR rail and ELW BFH barrel. Either just the upper, or upper and lower separately to save on the 11% excise tax. You'll get the free float rail, properly contoured barrel, and BCM qc.
As far as changing things introducing unforseen problems, that's what's made me hesitate on simply swapping out for a midlength barrel, gas tube, and gas block. I should probably just get a new upper before that point.
I do not currently have an optic, but I've had my eyes set on the COMP-M4, and the M300 light. Magazines are all PMAGS, and so far I've only been shooting Lake City 855, 193, and Federal .223 55gr. I plan to only shoot M855 (Lake City or IMI) out of it for practice going forward.
If I do go to midlength it sounds like my safest bet is to buy a BCM, DD, or the Geiselle URGI clone. But the practical thing to do right now would be to focus on practicing with it as it is and getting a good optic, light, and ammunition.
Somewhere on this forum you can find an older thread by Eurodriver. He put his personally owned 6920 through hell, to include running over it with a truck. Several times. It just kept on working. It finally stopped working when it took a tumble down a cliff, and I think the impact caused the barrel to bend.
My opinion, shoot your 6920 and verify function. Then lube it, load it, and drive on. And don’t throw it off a mountainside.
As far as changing things introducing unforseen problems, that's what's made me hesitate on simply swapping out for a midlength barrel, gas tube, and gas block. I should probably just get a new upper before that point.
I do not currently have an optic, but I've had my eyes set on the COMP-M4, and the M300 light. Magazines are all PMAGS, and so far I've only been shooting Lake City 855, 193, and Federal .223 55gr. I plan to only shoot M855 (Lake City or IMI) out of it for practice going forward.
If I do go to midlength it sounds like my safest bet is to buy a BCM, DD, or the Geiselle URGI clone. But the practical thing to do right now would be to focus on practicing with it as it is and getting a good optic, light, and ammunition.
Don’t waste your money on M855. M193 clones are cheaper and work just as well at putting holes in paper. Use something better for putting holes in people.
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echo5whiskey
01-04-19, 23:46
Don’t waste your money on M855. M193 clones are cheaper and work just as well at putting holes in paper. Use something better for putting holes in people.
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Truth. There is a lot of reliable information around on viable defensive ammo.
Something I've been considering was re-barreling my 6920 with the same barrel the URGI uses by Daniel Defense, but I'm not sure if that's an efficient option.
You are more likely to have a problem with the gun if you have it rebarreled than you are if you leave it as it is. Someone could muck up the rebarreling.
This really is getting silly. It's not like you are going to be going the Afghanistan or Iraq and firing 500 rounds a day in the middle of a sandstorm for weeks on end without sufficient opportunity to clean or lubricate it.
You are talking about taking it to the range and practice and hopefully taking a shooting course or two with plenty of opportunity to lubricate it.
Using the exact same gun that you have, many people have taken 2-3 day classes where they may be firing 500-700 rounds a day and never experienced a single malfunction. As long as you are using good magazines and good ammo, you should be fine.
I would add the Aimpoint pro. You will be amazed how much faster and easier you can engage targets.
Something must be in the water lately.
Buy quality, then think less, shoot / train more.
It sounds like you really just need to to shoot it more to become comfortable with it running.
M855 is generally both more expensive and less accurate than M193. Put that price difference towards gear and training.
The idea of changing the barrel (or a complete upper) to a midlength is fine, but is not needed and not the priority vs the gear and training.
vicious_cb
01-05-19, 01:06
Shoot it till it dies. I guarantee it will make you better informed on your next purchase decision.
As far as changing things introducing unforseen problems, that's what's made me hesitate on simply swapping out for a midlength barrel, gas tube, and gas block. I should probably just get a new upper before that point.
I do not currently have an optic, but I've had my eyes set on the COMP-M4, and the M300 light. Magazines are all PMAGS, and so far I've only been shooting Lake City 855, 193, and Federal .223 55gr. I plan to only shoot M855 (Lake City or IMI) out of it for practice going forward.
If I do go to midlength it sounds like my safest bet is to buy a BCM, DD, or the Geiselle URGI clone. But the practical thing to do right now would be to focus on practicing with it as it is and getting a good optic, light, and ammunition.
You have a Colt 6920, an AR that's about as reliable and durable as it gets. Don't even think about middies or uppers or gas blocks or any of that nonsense until you have sent at least a couple thousand rounds down range with your Colt.
I bought a car. I wont share the brand or model, so as to avoid that debate. I bought it hoping it would be reliable...but unsure. 100k + miles and 3 years later, and it has indeed proven reliable. I also have figured out the correct PM for various parts. Based on actual wear and experience. I feel very comfortable with the car, but also understand that it is a manmade, mechanical thing. I suggest you do the same thing with your 6920. Drive it for 100k miles and see what you see.
Don’t waste your money on M855. M193 clones are cheaper and work just as well at putting holes in paper. Use something better for putting holes in people.
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Moreover, i shoot steel. Many courses involve steel. M855 wears it out faster, and costs more. Dont pay to be a dick.
Moreover, i shoot steel. Many courses involve steel. M855 wears it out faster, and costs more. Dont pay to be a dick.
Good point. A lot of courses won’t even allow it.
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How many of you 6920 lovers are running a stock one as your primary? Yeah I thought so, I agree that it makes a good foundation rifle but that FSP is so limiting I think you are doing a disservice to novices by pushing it. I used to like the FSP but nowadays feel a slim 13.5 mlok rail as optimal, this post here shows one option, look at post 8 and 9.
https://www.m4carbine.net/showthread.php?209496-My-latest-M4-gery
To the OP'er, do what you want, but be aware that some are pushing a 1980's upper configuration as the way to go and we have come quite a ways since then. And all this worry about switching or pulling barrels, it has been done literally millions of times, even the SOCOM URG-1 is being supplied as a barrel/rail kit to be installed on existing military uppers. If you do it just confirm function afterwards.
How many of you 6920 lovers are running a stock one as your primary?
Define "stock". If you mean "Don't even change the furniture", then no I'm not.
No one is telling SouthwestAviator to buy a 6920. He already has one. No one is telling him to not modify his 6920. We're telling him to shoot his 6920 before spending money switching gas systems, barrels or buying a new upper for reliability. His 6920 is already reliable. SouthwestAviator is concerned about the reliability of the carbine gas system of his 6920. We're telling him there are no concerns. Nothing more.
Shoot Before Modifying. Ammo Before Accessories.
Hammer_Man
01-05-19, 09:55
How many of you 6920 lovers are running a stock one as your primary? Yeah I thought so, I agree that it makes a good foundation rifle but that FSP is so limiting I think you are doing a disservice to novices by pushing it. I used to like the FSP but nowadays feel a slim 13.5 mlok rail as optimal, this post here shows one option, look at post 8 and 9.
https://www.m4carbine.net/showthread.php?209496-My-latest-M4-gery
To the OP'er, do what you want, but be aware that some are pushing a 1980's upper configuration as the way to go and we have come quite a ways since then. And all this worry about switching or pulling barrels, it has been done literally millions of times, even the SOCOM URG-1 is being supplied as a barrel/rail kit to be installed on existing military uppers. If you do it just confirm function afterwards.
His concern is the reliability of the carbine gas system of his current rifle, not the ergonomic layout. To which most of us agree, his current 6920 is very reliable, and should serve him well for a long time.
If I do go to midlength it sounds like my safest bet is to buy a BCM, DD, or the Geiselle URGI clone. But the practical thing to do right now would be to focus on practicing with it as it is and getting a good optic, light, and ammunition.
I think you should shoot the rifle you have and discover if has things about it that in practice might make you prefer a different rifle, rather than obsessing about things that you think might, someday, theoretically make the rifle fail to meet your needs or expectations. You are massively overthinking the issue.
Somewhere on this forum you can find an older thread by Eurodriver. He put his personally owned 6920 through hell, to include running over it with a truck. Several times. It just kept on working. It finally stopped working when it took a tumble down a cliff, and I think the impact caused the barrel to bend.
My opinion, shoot your 6920 and verify function. Then lube it, load it, and drive on. And don’t throw it off a mountainside.
And don't fall off of a mountain... I have a friend in Alaska who was out hunting for mountain sheep. He got one, cut it up and put the meat in his pack. He then went to return home but in the process fell off of the mountain. He landed on his rifle which broke two things; his hip and the rifle. A bear happened along as they do in AK and there he was with a broken rifle and his pistol was in his pack which landed nearby. The bear knew a good thing we he saw it and took the pack of meat and the pistol. Support your right to arm bears.
To the OP, years ago I took the advice you've read here and bought a Colt carbine and Aimpoint Pro. In 7 years both have never failed to function and lately they've been getting a good workout with 2 gun matches. I'm on my second battery in the Aimpoint and the first still worked it was just getting old.
SouthwestAviator
01-05-19, 11:40
I bought a car. I wont share the brand or model, so as to avoid that debate. I bought it hoping it would be reliable...but unsure. 100k + miles and 3 years later, and it has indeed proven reliable. I also have figured out the correct PM for various parts. Based on actual wear and experience. I feel very comfortable with the car, but also understand that it is a manmade, mechanical thing. I suggest you do the same thing with your 6920. Drive it for 100k miles and see what you see.
Good analogy. I'm going to buy another 2,000 rounds to put through it. If it can get through that with no stoppages, I'd have quite a bit more faith in it. I wouldn't be shooting all 2,000 at once or in one range trip, and there'd be regular cleanings in between.
As far as the ergonomics, so far it seems to fit my needs very well. Worst case scenario I could have the FSB filed down to low profile if it bothers me that much once I have an optic, but I actually like having the fixed front sight base gas block. I'm going to put another 2,000 rounds through it before I determine whether I need to modify it. So far all it's got is a BlueForce sling and it's served well. As of yet there's nothing that really jumps out at me that needs changing, other than putting on an Aimpoint, except maybe the handguards. But even those, with the double heat shield, have done an amazing job at managing heat.
I've considered a LMT Enhanced BCG, but I'm wary of unintentionally "enhancing" my rifle into having stoppages.
The reason I was considering only shoot M855 for practice is because I figure that's what the M4 was designed to shoot and would prove the most reliable. But I've shot a good bit of M193 without any problems. Neither would be what I keep in it for defense. I plan to get some Federal Trophy Bonded Bear Claw for that.
Good analogy. I'm going to buy another 2,000 rounds to put through it. If it can get through that with no stoppages, I'd have quite a bit more faith in it. I wouldn't be shooting all 2,000 at once or in one range trip, and there'd be regular cleanings in between.
As far as the ergonomics, so far it seems to fit my needs very well. Worst case scenario I could have the FSB filed down to low profile if it bothers me that much once I have an optic, but I actually like having the fixed front sight base gas block. I'm going to put another 2,000 rounds through it before I determine whether I need to modify it. So far all it's got is a BlueForce sling and it's served well. As of yet there's nothing that really jumps out at me that needs changing, other than putting on an Aimpoint, except maybe the handguards. But even those, with the double heat shield, have done an amazing job at managing heat.
I've considered a LMT Enhanced BCG, but I'm wary of unintentionally "enhancing" my rifle into having stoppages.
The reason I was considering only shoot M855 for practice is because I figure that's what the M4 was designed to shoot and would prove the most reliable. But I've shot a good bit of M193 without any problems. Neither would be what I keep in it for defense. I plan to get some Federal Trophy Bonded Bear Claw for that.
The M16 was actually designed in conjunction with M193.
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I've been deliberating over this issue for months. I bought a Colt 6920 as my main go-to rifle in 2016 specifically because I thought it was the most reliable AR15 I could buy. It has never jammed, but several months ago I started reading about the improved reliability of midlength gas systems and am doubting my purchase. In short, I want the most reliable AR15 I can get. I'm not interested in the bells and whistles of the KAC or URGI, but I am interested in maximum reliability. I'd rather not have to spend $2500 on just the rifle and would prefer something basic, but I will save up for that if that's what it takes.
What is the most reliable AR15? Do you have to go to KAC with the expensive features I don't want (such as the URX rail, flash hider, etc) to get the most reliable rifle?
(I also have a Colt AR15A4, but I'm starting to agree that it's a bit long for indoors use)
Something I've been considering was re-barreling my 6920 with the same barrel the URGI uses by Daniel Defense, but I'm not sure if that's an efficient option.
How many rnds have you put through it? While there's various reasons other brands may be superior, reliability is not likely one of them to that Colt. So buy another AR. Problem/OCD solved. Is a BMW M3 a nicer car then a Honda civic? Yes. Is it more reliable? Nope. It's kinda like that.
nightchief
01-05-19, 12:50
I've considered a LMT Enhanced BCG, but I'm wary of unintentionally "enhancing" my rifle into having stoppages.
The LMT e-carrier will not gain significant benefit versus the Colt BCG that came with the rifle. For the cost of an LMT E-BCG, your over halfway price wise to the mid length upper you seek. My $.02.
You need to stop nukeing this and go shoot. When I started building my guns years ago I wanted to use my own at work. The armorer told me to shoot 1,000 rounds and then come talk to him. I did and he asked how many malfunctions I had. Zero. He said that's what I figured but I wanted you to know the rifle and have confidence in it. I've used that formula for any build that was going into harms way and it hasn't let me down. So go put a thousand rounds through it and then see if your concerns are still there. I'll wager they're not. Go shoot the gun, a lot, with good training while you're at it.
SouthwestAviator
01-05-19, 14:07
You need to stop nukeing this and go shoot. When I started building my guns years ago I wanted to use my own at work. The armorer told me to shoot 1,000 rounds and then come talk to him. I did and he asked how many malfunctions I had. Zero. He said that's what I figured but I wanted you to know the rifle and have confidence in it. I've used that formula for any build that was going into harms way and it hasn't let me down. So go put a thousand rounds through it and then see if your concerns are still there. I'll wager they're not. Go shoot the gun, a lot, with good training while you're at it.
Just ordered 1000 rounds. Gonna put it through it's paces some more.
As far as lubricant, I've been using Safariland (formerly Breakfree) CLP. Is this the best CLP to use for cleaning and lubrication? I've read that the G96 CLP is the current mil-spec one, and that Safariland CLP no longer is milspec. I've also read that if Safariland CLP and G96 CLP mix, it creates a glue-like substance. I was considering switching to G96 but if that's the case maybe I should just stick with Safariland.
I've been deliberating over this issue for months. I bought a Colt 6920 as my main go-to rifle in 2016 specifically because I thought it was the most reliable AR15 I could buy. It has never jammed, but several months ago I started reading about the improved reliability of midlength gas systems and am doubting my purchase. In short, I want the most reliable AR15 I can get. I'm not interested in the bells and whistles of the KAC or URGI, but I am interested in maximum reliability. I'd rather not have to spend $2500 on just the rifle and would prefer something basic, but I will save up for that if that's what it takes.
What is the most reliable AR15? Do you have to go to KAC with the expensive features I don't want (such as the URX rail, flash hider, etc) to get the most reliable rifle?
(I also have a Colt AR15A4, but I'm starting to agree that it's a bit long for indoors use)
Something I've been considering was re-barreling my 6920 with the same barrel the URGI uses by Daniel Defense, but I'm not sure if that's an efficient option.
I think you made a sensible choice. You really don't need to be concerned with carbine over midlength anymore than the unnecessary concern with a DI over a piston system imho.
Just ordered 1000 rounds. Gonna put it through it's paces some more.
As far as lubricant, I've been using Safariland (formerly Breakfree) CLP. Is this the best CLP to use for cleaning and lubrication? I've read that the G96 CLP is the current mil-spec one, and that Safariland CLP no longer is milspec. I've also read that if Safariland CLP and G96 CLP mix, it creates a glue-like substance. I was considering switching to G96 but if that's the case maybe I should just stick with Safariland.
I've used Eezox for years and
Mil-Comm TW25B "Grease" with great results but your likely to get many different suggestions including even using motor oil. To each his own
Just ordered 1000 rounds. Gonna put it through it's paces some more.
As far as lubricant, I've been using Safariland (formerly Breakfree) CLP. Is this the best CLP to use for cleaning and lubrication? I've read that the G96 CLP is the current mil-spec one, and that Safariland CLP no longer is milspec. I've also read that if Safariland CLP and G96 CLP mix, it creates a glue-like substance. I was considering switching to G96 but if that's the case maybe I should just stick with Safariland.
Keep the lube you have, it’ll work fine.
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I'm a casual reader and rare poster here, and I know I don't likely shoot as much as most others on this page, but here's my 2 cents on the matter: The first AR I bought for myself was a LE6920, circa early 2011, after browsing this forum quite a bit. Since then I've built a number of rifles in various configurations, as well as buying another 6920 a couple of years ago. (The wife has one and I have one situated for what we each prefer.) Recently I bought a KAC SR-15 Mod 2, and it has spoiled me for all others, to be perfectly honest. (Although I put an Ergo grip on it, in place of the A2 that came with it.) Over the next few weeks, I'm going to buy another one (18" LPR version) and start parting out my builds to friends and family. Everything but the 6920's, I'm hanging on to those. Do not hesitate to shoot yours a lot, it's a fine rifle and should hold up well. There are better rifles, and things you might do to make it better than it is now, but take the time to see what needs to be changed before guessing at what might be better. I assure you, your money was not wasted, so let go of the buyer's remorse, you could have done so much worse.
My current main 'home defense' gun is the later 6920, a model that came OEM with Magpul SL furniture. I added a light, a PRO, an ambi CH, a sling, and a QMS trigger. Those are all preferences I gained from shooting the first 6920 a lot and then tinkering with things I thought would make it perform better, a philosophy I learned here. The light, optic, and sling are obvious no-brainers, and I'd even say an ambi CH (or at least one with an enhanced latch) is a close 4th. The only reason I switched out the trigger (did the same on the other one) is because I'd heard there were problems with the notched hammer that comes on the rifle. I don't think I've ever seen a real case to support that fear, but as it turns out the QMS feels better than the stock triggers, at least with the two I have.
55354
SouthwestAviator
01-05-19, 16:12
I'm a casual reader and rare poster here, and I know I don't likely shoot as much as most others on this page, but here's my 2 cents on the matter: The first AR I bought for myself was a LE6920, circa early 2011, after browsing this forum quite a bit. Since then I've built a number of rifles in various configurations, as well as buying another 6920 a couple of years ago. (The wife has one and I have one situated for what we each prefer.) Recently I bought a KAC SR-15 Mod 2, and it has spoiled me for all others, to be perfectly honest. (Although I put an Ergo grip on it, in place of the A2 that came with it.) Over the next few weeks, I'm going to buy another one (18" LPR version) and start parting out my builds to friends and family. Everything but the 6920's, I'm hanging on to those. Do not hesitate to shoot yours a lot, it's a fine rifle and should hold up well. There are better rifles, and things you might do to make it better than it is now, but take the time to see what needs to be changed before guessing at what might be better. I assure you, your money was not wasted, so let go of the buyer's remorse, you could have done so much worse.
My current main 'home defense' gun is the later 6920, a model that came OEM with Magpul SL furniture. I added a light, a PRO, an ambi CH, a sling, and a QMS trigger. Those are all preferences I gained from shooting the first 6920 a lot and then tinkering with things I thought would make it perform better, a philosophy I learned here. The light, optic, and sling are obvious no-brainers, and I'd even say an ambi CH (or at least one with an enhanced latch) is a close 4th. The only reason I switched out the trigger (did the same on the other one) is because I'd heard there were problems with the notched hammer that comes on the rifle. I don't think I've ever seen a real case to support that fear, but as it turns out the QMS feels better than the stock triggers, at least with the two I have.
55354
Very nice set up. I find it interesting that your main home defense gun is the 6920 instead of your KAC. Is this just because you want a relatively basic carbine for that role, or because you don't want to risk the KAC being taken in as evidence in the event you have to use it? I've always just been attracted to the more basic carbines for ARs without bells and whistles other than a sling, light, optic, etc. Part of why I got the 6920 in the first place, to have a tough-as-nails basic carbine with maximum reliability.
Very nice set up. I find it interesting that your main home defense gun is the 6920 instead of your KAC. Is this just because you want a relatively basic carbine for that role, or because you don't want to risk the KAC being taken in as evidence in the event you have to use it? I've always just been attracted to the more basic carbines for ARs without bells and whistles other than a sling, light, optic, etc. Part of why I got the 6920 in the first place, to have a tough-as-nails basic carbine with maximum reliability.
It's mainly due to my wife being more familiar with the basic M4-style of rifle. She's former active duty/current reserves, and although not in a field that normally handles them outside of qualifications for deployment, she likes to stay in practice. At some point the SR-15 will take its place, and I will have my 6920 as the 'knock around' rifle. She hasn't even fired the SR-15 once yet, so I don't want to change things up until she has some experience with it.
SouthwestAviator
01-05-19, 16:33
It's mainly due to my wife being more familiar with the basic M4-style of rifle. She's former active duty/current reserves, and although not in a field that normally handles them outside of qualifications for deployment, she likes to stay in practice. At some point the SR-15 will take its place, and I will have my 6920 as the 'knock around' rifle. She hasn't even fired the SR-15 once yet, so I don't want to change things up until she has some experience with it.
Makes sense. Does reliability play a factor in your decision to switch to the SR-15 from the Colt, or does it have more to do with the superior ergonomics and shooting characteristics?
Makes sense. Does reliability play a factor in your decision to switch to the SR-15 from the Colt, or does it have more to do with the superior ergonomics and shooting characteristics?
It's the latter, mainly. The KAC lower is fully ambidextrous (although the charging handle was not, I did change that out too. Geissele Black Friday Sale was the main driver there) and the gas system makes for a softer recoil/impulse. The other thing was the E3 bolt. For my age and amount I shoot, I should not have to worry about wearing it out in my lifetime. That said? I still bought a replacement bolt and bolt/firing pin rebuild kit, just in case. Same reason I replaced the FCG in the 6920, just in case.*
I don't have any doubts about the reliability of the 6920. The first one I have that is coming up on 8 years old has several thousand rounds through it (including 2k of Wolf steel case I got cheap) and has been dropped in mud and sand has not had any failures to do with the rifle itself. One time I suffered a major stoppage from some XM193 that was blowing out primers. An anvil got loose and hid out in the lower receiver, eventually jamming up the FCG. I was able to clear that by taking the FCG out and dropping the anvil out. Another time, I had some old ammo (like 20 years old) that my father gave me. I didn't realize how old it was and how long it had been in the mag. A few of the rounds were slightly corroding where it was touching the inside of the magazine, something must have got in it at some point. I learned this after it FTE the case and it was a motherf$%^er to get out. I de-loaded the mag and saw a few more rounds like it, ditched those in the unfired rounds container, no more issues. I had one mag with bent lips from being dropped that caused some feed issues, but otherwise, outside of maybe a few ammo-related failures that just required yanking the charging handle back and popping in a new round, I don't recall anything that made me question the rifle's reliability.
*In regard to the notched hammer concern: I have a Colt 6550 (pre-ban 20" A2 'Government' model, small pin FCG, big front pivot pin, no bayonet lug) from the late '80s that my dad handed down to me that has the same type of notched hammer as well as the 'neutered' carrier of the day. I can't tell you how many thousands of crappy gun show reload/re-manufactured ammo we dumped through that thing in two decades, but nary a problem with the FCG.
SouthwestAviator
01-05-19, 19:08
It's the latter, mainly. The KAC lower is fully ambidextrous (although the charging handle was not, I did change that out too. Geissele Black Friday Sale was the main driver there) and the gas system makes for a softer recoil/impulse. The other thing was the E3 bolt. For my age and amount I shoot, I should not have to worry about wearing it out in my lifetime. That said? I still bought a replacement bolt and bolt/firing pin rebuild kit, just in case. Same reason I replaced the FCG in the 6920, just in case.*
I don't have any doubts about the reliability of the 6920. The first one I have that is coming up on 8 years old has several thousand rounds through it (including 2k of Wolf steel case I got cheap) and has been dropped in mud and sand has not had any failures to do with the rifle itself. One time I suffered a major stoppage from some XM193 that was blowing out primers. An anvil got loose and hid out in the lower receiver, eventually jamming up the FCG. I was able to clear that by taking the FCG out and dropping the anvil out. Another time, I had some old ammo (like 20 years old) that my father gave me. I didn't realize how old it was and how long it had been in the mag. A few of the rounds were slightly corroding where it was touching the inside of the magazine, something must have got in it at some point. I learned this after it FTE the case and it was a motherf$%^er to get out. I de-loaded the mag and saw a few more rounds like it, ditched those in the unfired rounds container, no more issues. I had one mag with bent lips from being dropped that caused some feed issues, but otherwise, outside of maybe a few ammo-related failures that just required yanking the charging handle back and popping in a new round, I don't recall anything that made me question the rifle's reliability.
*In regard to the notched hammer concern: I have a Colt 6550 (pre-ban 20" A2 'Government' model, small pin FCG, big front pivot pin, no bayonet lug) from the late '80s that my dad handed down to me that has the same type of notched hammer as well as the 'neutered' carrier of the day. I can't tell you how many thousands of crappy gun show reload/re-manufactured ammo we dumped through that thing in two decades, but nary a problem with the FCG.
Good to hear. Like I said, I bought the 6920 because of it's reputation for reliability. I've never heard of this notched hammer issue though. What kind of problems have people reported with them, and what's the cause?
Gunsnguitars
01-05-19, 19:40
You have a Colt 6920, an AR that's about as reliable and durable as it gets. Don't even think about middies or uppers or gas blocks or any of that nonsense until you have sent at least a couple thousand rounds down range with your Colt.
^This is exactly what I'm thinking. The Colt 6920 is considered by many as a gold standard for what a basic AR is supposed to be in terms of reliability, durability, etc...Lots of folks depend on much lesser quality rifles everyday and they lose no sleep over them. Less is more. For a basic, reliable AR, I believe the 6920 is just about as good as it gets in terms of value. If it ain't broke don't fix it. The 6920 is a fine rifle. Count your blessings. Things could be much worse. Shoot it until it breaks. Good luck with that....
Good to hear. Like I said, I bought the 6920 because of it's reputation for reliability. I've never heard of this notched hammer issue though. What kind of problems have people reported with them, and what's the cause?
The concern was that the notch could somehow bind up with the carrier/cause too much friction, or something along those lines. I've never heard of a case where that has actually happened myself, but at the time (8 years ago?) I figured it was better safe than sorry. It has just been a habit since then. With as many 6920s in use in both civilian and LEO hands, I think if it were an actual concern we would have heard horror stories long before now.
How many of you 6920 lovers are running a stock one as your primary? Yeah I thought so, .
I do. All 3 are stock. In fact all my firearms are. I despise playing with accessories. Buying, trying..etc... if I can't get my hands on one to try first I don't buy. Can't stand spending hundreds on something I may not like then having to try and sell it and loose money.
Just want to shoot.
SouthwestAviator
01-05-19, 21:47
The concern was that the notch could somehow bind up with the carrier/cause too much friction, or something along those lines. I've never heard of a case where that has actually happened myself, but at the time (8 years ago?) I figured it was better safe than sorry. It has just been a habit since then. With as many 6920s in use in both civilian and LEO hands, I think if it were an actual concern we would have heard horror stories long before now.
Ah, I see. Well, for me, changing out the hammer is something I'd do if I wasn't afraid of messing up the FCG more than the notched hammer potentially causing issues. Thanks for filling me in.
I can sympathize with your second guessing but you are getting good advise here. When I was new to fighting ARs I reaserched the hell out of everything and ended up with a 6920 about 8 years ago. My prior experience with firearms was heavily focused on custom 1911s. I learned real fast ARs are nothing like 1911’s. If you buy a good off the shelf one they just run.
I used to use different lube on my target pistols based on the weather. For my ARs red axel grease and synthetic model 1 works fine. After about 500 rounds my original 6920 felt like the bolt was on ball bearings. I grease things that slide and oil things that turn. Also, because Colt used the smaller mil spec gas port the gun runs smoother than many other brands.
I worried about mid length until I ran it through a few classes and realized it doesn’t matter. The gun ran well and ate every type of ammo I gave it. Just buy good mags...but that goes for any gun.
Slip 2000 EWL is a great lube, btw. Non-petroleum based, non-toxic, doesn't smell, doesn't burn off, withstands high temps, and doesn't gum up in storage. G96 is what BCM uses for that "new gun smell" but they've included free Slip 2000 EWL the past couple times I ordered uppers from them. Grease is okay on the charging handle and trigger contact points but on a bcg you risk it forming a thick paste when too much carbon fouling mixes with it, whereas an oil lube stays viscous and even washes away some of the fouling.
Slip 2000 EWL is a great lube, btw. Non-petroleum based, non-toxic, doesn't smell, doesn't burn off, withstands high temps, and doesn't gum up in storage. G96 is what BCM uses for that "new gun smell" but they've included free Slip 2000 EWL the past couple times I ordered uppers from them.
Past several years IME. I love that smell.
thegreyman
01-06-19, 08:39
https://classic.motown.com/story/supremes-stop-name-love/ Record sounds broken?
:stop: this thread or I will have to buy a dead horse to whip.
everready73
01-06-19, 09:51
You don't have to be anal about detail cleaning it after every use either. Google filthy 14. I use G96 but most any lube will work fine. Just stay away from frog lube which will gunk up and cause issues if your gun sits for a while.
I lube my BCG really good before shooting and wipe it down every 1k rounds or so. Tim a bore snake through every once in a while and never had an issue. Abuse the rifle a bit and you will see it has capable of more than you thought
SouthwestAviator
01-06-19, 10:08
Keep the lube you have, it’ll work fine.
Sent from my iPhone using Tapatalk
Think I'm gonna go with this advice for now. It's worked fine thus far.
Let's help this guy out.
Ok combat vets, show of hands: how many of you, in the middle of a firefight looked at your M4 and thought "damn it, I knew I should have grabbed the midlength at the armory!"
You can always just build another. Nothing wrong with the colt as a first rifle. Use what you’ve learned and start stockpiling parts.
KISS mutt
https://uploads.tapatalk-cdn.com/20190106/b78a2ddb6565d03d0026d9b9795a216b.jpg
I only read the first 2 posts so forgive me if this has already been said. I.G. Nailed it in post 2.
Let's help this guy out.
Ok combat vets, show of hands: how many of you, in the middle of a firefight looked at your M4 and thought "damn it, I knew I should have grabbed the midlength at the armory!"
In Central America (1984-1985) I carried a worn out CAR-15 (XM177) in my aircraft. It must have been 1960's vintage. It always would shoot, but had a tendency once in a while to pop off two rounds when on semi-auto. Probably a worn disconnector. OP, you can't go wrong with any of the AR's mentioned. I personally own Colt and LMT. My oldest is an AR15-HBAR from 1988. Never had any kind of failure. Buy it, shoot it, enjoy it and don't worry. If by rare chance it does fail you, use it as a club and then whip out a revolver and shoot the bad guy.
SouthwestAviator
01-07-19, 13:50
In Central America (1984-1985) I carried a worn out CAR-15 (XM177) in my aircraft. It must have been 1960's vintage. It always would shoot, but had a tendency once in a while to pop off two rounds when on semi-auto. Probably a worn disconnector. OP, you can't go wrong with any of the AR's mentioned. I personally own Colt and LMT. My oldest is an AR15-HBAR from 1988. Never had any kind of failure. Buy it, shoot it, enjoy it and don't worry. If by rare chance it does fail you, use it as a club and then whip out a revolver and shoot the bad guy.
What kind of shooting schedule did you have with that? Also, the LMT MRP CQB 16 upper is my primary consideration whenever it is I happen to buy another upper.
What kind of shooting schedule did you have with that? Also, the LMT MRP CQB 16 upper is my primary consideration whenever it is I happen to buy another upper.
I had it tied down in my aircraft most of the time when flying, and close at hand when not flying. Otherwise just a rotation of ammo in that humid climate of Honduras and southeast from there. Used to pop off a round or two into the trees once in a while 50 to 100 feet above the jungle tree tops to make sure it still worked. Different times and different world situation.
I just received an LMT MRP CQB as well but have not installed it on my lower. Took advantage of the Christmas Special they had. First AR piston set-up I have owned.
indianalex01
01-07-19, 18:47
Deleted
There has been some of the worst posts I’ve ever seen on this thread (including this one). Nobody who has been in a gun fight with an M4 has said “I wished I had brought a middy out”. We didn’t even have middys. I think people are trying to outdo each other with stupid posts.
His post was sarcasm...
indianalex01
01-07-19, 19:12
His post was sarcasm...
Yea I realized it after I posted. Lol. I guess I seen some bad ones prior to that one
Yea I realized it after I posted. Lol. I guess I seen some bad ones prior to that one
Can't disagree there.
nyc_paramedic
01-07-19, 20:26
Dear SouthwestAviator,
I'm afraid that you have gotten the most terrible advice, and from the most despicable of scoundrels, here at m4carbine.net. The rifle you seek does, in fact, exist. It's called the Colt AR-15A3. But not just any Colt AR-15A3, or said rifle in any particular configuration. It is a specific serial number Colt AR-15A3 --one which I cannot reveal to you, as it had been hidden from view with black tape.
To make matters worse, the holy grail of the most reliable self defense rifle in the world, can only been seen in one video on a website called "Youtube". The title, if you so choose to begin and commit to this daring quest, is called, "Colt AR-15s Never Wear Out: Beat Up Cop Gun. In this moving picture, you will witness a savage, awkward and inelegant beast, --who also makes the most discordant and repugnant high pitched noises, as if wishing to communicate with the civilized world-- molest this Colt AR-15A3 rifle over 3 dozen times and in the most vile and unsavoury ways. His breath has most certainly scorched the anodizing of this spectacular specimen of a rifle but seems no worse for wear. You will witness that this rifle continues to function flawlessly though subjected to some of the harshest and stupefying conditions known to mankind.
Take note: His creators have seen fit to brand this beast with multiple Velcro identifiers bearing the letters "nutnfancy". Please don't ask me to decode this enigma. I'm fairly well read in the Western Classics cannon, but haven't the foggiest after giving it considerable thought. This is important as their are two organisms in this video; the other seemingly a bit more evolved and intelligent, if I can be so kind. Stay away from the former! It's quite possibly detrimental to your physical and/or mental faculties.
Find this rifle and you will achieve inner peace. Go forth and Godspeed!
N
SouthwestAviator
01-07-19, 21:18
Dear SouthwestAviator,
I'm afraid that you have gotten the most terrible advice, and from the most despicable of scoundrels, here at m4carbine.net. The rifle you seek does, in fact, exist. It's called the Colt AR-15A3. But not just any Colt AR-15A3, or said rifle in any particular configuration. It is a specific serial number Colt AR-15A3 --one which I cannot reveal to you, as it had been hidden from view with black tape.
To make matters worse, the holy grail of the most reliable self defense rifle in the world, can only been seen in one video on a website called "Youtube". The title, if you so choose to begin and commit to this daring quest, is called, "Colt AR-15s Never Wear Out: Beat Up Cop Gun. In this moving picture, you will witness a savage, awkward and inelegant beast, --who also makes the most discordant and repugnant high pitched noises, as if wishing to communicate with the civilized world-- molest this Colt AR-15A3 rifle over 3 dozen times and in the most vile and unsavoury ways. His breath has most certainly scorched the anodizing of this spectacular specimen of a rifle but seems no worse for wear. You will witness that this rifle continues to function flawlessly though subjected to some of the harshest and stupefying conditions known to mankind.
Take note: His creators have seen fit to brand this beast with multiple Velcro identifiers bearing the letters "nutnfancy". Please don't ask me to decode this enigma. I'm fairly well read in the Western Classics cannon, but haven't the foggiest after giving it considerable thought. This is important as their are two organisms in this video; the other seemingly a bit more evolved and intelligent, if I can be so kind. Stay away from the former! It's quite possibly detrimental to your physical and/or mental faculties.
Find this rifle and you will achieve inner peace. Go forth and Godspeed!
N
Indeed, in the past I have stumbled across the very video you speak of. I know not what to make of the creatures handling the rifle in that video, but it does go to show what kind of horrors that rifle can stand up against and still function flawlessly. I will undertake this quest with the same unwavering resolve George Washington's troops possessed when crossing the Delaware into dangers only imaginable.
In the meantime, I'll enjoy this 6920 and the ammo I have coming in for it! I've come to figure that if this basic carbine isn't more than reliable enough, then I wouldn't have much faith in other iterations of the same family of weapons.
Yea I realized it after I posted. Lol. I guess I seen some bad ones prior to that one
Next time I'll add a smilie.
Gen Sherman
01-11-19, 07:48
Good point. A lot of courses won’t even allow it.
Sent from my iPhone using Tapatalk
Yup. Where I'm at, no range that allows AR's, will allow steel ammo. No go.
OP: seems to me you have not researched carbine length, mid-length and rifle length
gas systems. Do your research.
You'll find that there is nothing wrong with a carbine length gas system. It's been
proven for decades in the military services and civilian community with AR15's.
Is mid-length gas system mil-spec??????
Look up the answer. What's the benefit of mid-length over carbine length system???
The Colt you have is just about as solid as one will come out of the box for the dollars you spent.
Yeah, you can spend $2500 on another brand for bells/whistles, but I doubt one of those $2500
guns will out last the Colt.....meh.
ETA: The Colt is the 'benchmark' of AR's which all other AR's are measured by.
Desert Trekker
01-11-19, 08:43
Colt is very reliable. Mid length gas systems are NOT more reliable than carbine length gas systems. The advantage of a mid length gas system is reduced recoil. The sum of the parts and how they are put together determines reliability.
I use Colt and BCM rifles in the AR15 platform because they have a proven track record of accuracy, dependability and durability. I use both mid length and carbine length gas systems.
Gen Sherman
01-11-19, 08:55
BTW OP, what did many dealers say about AR's during the assault weapons ban???
""ABC"" = Always Buy Colt. They hold their value VERY well.
Colt is very reliable. Mid length gas systems are NOT more reliable than carbine length gas systems. The advantage of a mid length gas system is reduced recoil. The sum of the parts and how they are put together determines reliability.
I use Colt and BCM rifles in the AR15 platform because they have a proven track record of accuracy, dependability and durability. I use both mid length and carbine length gas systems.
Yup. Where I'm at, no range that allows AR's, will allow steel ammo. No go.
OP: seems to me you have not researched carbine length, mid-length and rifle length
gas systems. Do your research.
You'll find that there is nothing wrong with a carbine length gas system. It's been
proven for decades in the military services and civilian community with AR15's.
Is mid-length gas system mil-spec??????
Look up the answer. What's the benefit of mid-length over carbine length system???
The Colt you have is just about as solid as one will come out of the box for the dollars you spent.
Yeah, you can spend $2500 on another brand for bells/whistles, but I doubt one of those $2500
guns will out last the Colt.....meh.
ETA: The Colt is the 'benchmark' of AR's which all other AR's are measured by.
You guys aren't aware of the Crane testing mentioned earlier are you? I'd read it and then forgotten what it said, you both should take a look.
johnnywitt
01-11-19, 12:28
I would add that if using a Carbine Length Gas System the optimal length is a 14.5" barrel. If you are using a 16" barrel, then a Mid Lenth Gas System is more reliable. Lastly, for a work around on the overgassed Carbine Gas w/ a 16" barrel, just use any .223 ammo (lower pressures).
You guys aren't aware of the Crane testing mentioned earlier are you? I'd read it and then forgotten what it said, you both should take a look.
At the risk of getting sidetracked, is this what you were talking about: http://soldiersystems.net/2018/05/14/nswc-crane-carbine-mid-length-gas-system-testing-shows-increased-performance/
So far, Crane has put 30,400 rounds of M855A1 through three M4A1s equipped with 14.5″ cold hammer forged barrels and a mid-gas system with a gas block approximately 9.8″ from the bolt face.
They stated SOF M4A1s normally start to see accuracy degradation at around 6,000 rounds. But during testing of the mid-gas system, they’d hit 12,600 and still hadn’t seen any changes.
They also have only broken one bolt so far in testing, although I don’t think they’re ready to attribute the improved bolt performance to the mid-gas system.......
.........Although testing to 34,000 rounds isn’t yet complete, the conclusion is simple. Use of a mid-gas system significantly extends the life of the overall weapon system. It also offers increased performance over a carbine-length gas system.
The advantage of a mid length gas system is reduced recoil.
This is one of those myths I wish would go away. All else being equal- muzzle velocity, payload mass, weapon mass- free recoil is the same, regardless of the length of the gas system. This is true whether the firearm is self loading or manually loaded. If the length of the gas system has any effect on recoil, it's felt recoil. How the shooter perceives the recoil. Is is softer? Sharper? Quicker? Longer duration?- and so on. Not how much recoil energy is generated.
indianalex01
01-12-19, 00:33
This is one of those myths I wish would go away. All else being equal- muzzle velocity, payload mass, weapon mass- free recoil is the same, regardless of the length of the gas system. This is true whether the firearm is self loading or manually loaded. If the length of the gas system has any effect on recoil, it's felt recoil. How the shooter perceives the recoil. Is is softer? Sharper? Quicker? Longer duration?- and so on. Not how much recoil energy is generated.
I like that this post. The only area that I want to add to it is that gas port size can make a difference with sharper recoil.
I would add that if using a Carbine Length Gas System the optimal length is a 14.5" barrel. If you are using a 16" barrel, then a Mid Lenth Gas System is more reliable. Lastly, for a work around on the overgassed Carbine Gas w/ a 16" barrel, just use any .223 ammo (lower pressures).
Actually from the M4 testing the optimal barrel length for carbine gas was determined to be 13", it was increased to 14.5 to allow for bayonet mounting.
Desert Trekker
01-12-19, 10:11
This is one of those myths I wish would go away. All else being equal- muzzle velocity, payload mass, weapon mass- free recoil is the same, regardless of the length of the gas system. This is true whether the firearm is self loading or manually loaded. If the length of the gas system has any effect on recoil, it's felt recoil. How the shooter perceives the recoil. Is is softer? Sharper? Quicker? Longer duration?- and so on. Not how much recoil energy is generated.
From Oxford Dictionary: recoil 2.1 (of a gun) move abruptly backwards as a reaction on firing a bullet, shell, or other missile.
Most forum viewers will think of recoil as the amount of force pushed into their shoulder. This is what was addressed in my initial post. An increase in pressure directed to the bolt will increase "felt" recoil. Pressure can be increased in several ways: more powder, increasing the gas port size, and increasing the dwell time. Dwell time is increased by placing the gas port closer to the bolt. The genesis of the mid length gas system was an effort to reduce recoil and the success of this effort is obvious.
Actually from the M4 testing the optimal barrel length for carbine gas was determined to be 13", it was increased to 14.5 to allow for bayonet mounting.
Do you happen to have a link or document name to support this? Not questioning your veracity, but would love to read the 13” optimum within testing.
Note: "Ejecta" is the mass of projectile and powder. I mistakenly called it "Payload Mass" in my other post. The bullet is the payload but it's also part of the ejecta. The ejecta consists of the bullet and the gas.
From Oxford Dictionary: recoil 2.1 (of a gun) move abruptly backwards as a reaction on firing a bullet, shell, or other missile.
Most forum viewers will think of recoil as the amount of force pushed into their shoulder. This is what was addressed in my initial post. An increase in pressure directed to the bolt will increase "felt" recoil. Pressure can be increased in several ways: more powder, increasing the gas port size, and increasing the dwell time. Dwell time is increased by placing the gas port closer to the bolt. The genesis of the mid length gas system was an effort to reduce recoil and the success of this effort is obvious.
The Oxford Dictionary defines recoil in the simplest of lay terms. As shooters striving to expand our knowledge, we have to realize there is more aspects to recoil than the dictionary covers. "Felt Recoil" and "Free Recoil" are inter-related but also significantly different. "Felt Recoil" is how the shooter perceives recoil. Free Recoil is how much recoil force is transferred to the shooter, the amount of force pushed into their shoulder. If a shooter wants to know "How do I reduce recoil?" the answer is always "Add mass to your firearm. Reduce ejecta mass. Reduce velocity." But if the shooter wants to change felt recoil, that another topic of discussion entirely.
Felt recoil is subjective and affected by any number of factors, such as buttpads, drop at comb, heel & toe angle, bore height over comb, operating system, type of clothing worn- you name it! Changes that soften recoil can actually increase recoil. A shooter might have a recoil pad installed that softens the recoil but lightens the rifle. More energy is transferred to the shooter, but it's softer and much more comfortable. Or the shooter might have a heavy brass buttplate installed. It adds mass to the rifle which decreases free recoil. But a brass buttplate is hard. Recoil transferred to the shooter is quicker, harder and all too often more painful. Less force to the shoulder but uncomfortably so.
Free recoil is objective and measurable and is affected by four specific factors- Muzzle Velocity, Ejecta Mass, Weapon Mass and the Constant Velocity of the Expanding Gas which is roughly 5700 fps. (The speed of the expanding gas is limited by bullet speed inside the bore but achieves full velocity once the bullet uncorks the muzzle. It's a significant part of recoil in high power rifle calibers.) These four factors are used to calculate how much is force pushed into the shoulder.
Taking mass away from the reciprocating parts reduces the overall mass of the firearm. Removing mass increases recoil- increases the force to the shoulder. It may feel softer, depending on how the speed of the reciprocating mass is tuned, but even by the definition found in the Oxford Dictionary, the result is more recoil.
I bought a BCM M4 with a 16” barrel about 5 years ago now and never had any problems with it. I shoot it at the range.and did a one day training class as well that put 500 rounds through it that day. I have other rifles but this is my only carbine length rifle. My others are mid-length.
Do you happen to have a link or document name to support this? Not questioning your veracity, but would love to read the 13” optimum within testing.
Anecdotally- Back in the day, when the M4 first began entering the inventory, a very good in-depth article was printed in one of the gun mags, including information about the M4's development. The author stated he was told the development team played around with shortening the gas system until they found the shortest possible length that gave them 100% reliability, then added an inch or two for insurance (I don't recall the exact measurements). Using that port location, they set the barrel length to allow the mounting of an M16 bayonet.
BTW OP, what did many dealers say about AR's during the assault weapons ban???
""ABC"" = Always Buy Colt. They hold their value VERY well.
Pretty sure it was Armalite, Bushmaster, Colt.
I might be wrong, but I remember Lt. Col Dave Lutz making mention of this. You can probably search M4C and find it.
Do you happen to have a link or document name to support this? Not questioning your veracity, but would love to read the 13” optimum within testing.
Anecdotally- Back in the day, when the M4 first began entering the inventory, a very good in-depth article was printed in one of the gun mags, including information about the M4's development. The author stated he was told the development team played around with shortening the gas system until they found the shortest possible length that gave them 100% reliability, then added an inch or two for insurance (I don't recall the exact measurements). Using that port location, they set the barrel length to allow the mounting of an M16 bayonet.
I recall reading something like that. Even then I was pretty sceptical that the existing carbine length gas system with enough barrel to mount a bayonet... was coincidentally the same as the result of testing different gas system and barrel lengths for reliability.
Desert Trekker
01-12-19, 19:31
You guys aren't aware of the Crane testing mentioned earlier are you? I'd read it and then forgotten what it said, you both should take a look.
The referenced CRANE report can be viewed here:
https://partner-mco-archive.s3.amazonaws.com/client_files/1527866983.pdf
Note the report’s absence of salient details of the rifles used for comparison. The measured data is not in question. However, reliability is necessarily coupled to the components and their assembly. Now look at CRANE’s fumbled evaluation below and decide what level of confidence should be attributed to this carbine vs mid length evaluation.
Crane “Contaminates” SURG Test Samples By Crosspolinating Weapon Components Between Vendor Submissions, Calls On Offerors For New Samples
Friday, October 6th, 2017
Naval Surface Warfare Center – Crane in Indiana is responsible for the testing and procurement of USSOCOM’s weapons. One of the projects they have been working on for SOCOM is the Suppressor Upper Receiver Group, an upgrade of the M4A1 Lower Receiver Group will allow the Warfighter’s weapon to be optimized for continuous suppressed use.
Earlier this year, the program had its second go around after an initial attempt at identifying a system failed last year. Performance parameters were adjusted from the earlier effort to more accurately reflect what was possible, and vendors submitted three sample SURG candidates each.
Unfortunately during recent testing, sample weapons were incorrectly assembled using parts from different vendor submissions, undermining the integrity of the results.
Last week, Crane contacted vendors and informed them that any offeror which had passed Phase I could resubmit three samples by 26 October in order to continue participation in the solicitation.
The government will then reaccomplish Phase I and then move on to Phases I & III with the resubmitted samples.
Additionally, Crane has outlined measures it will take to prevent future crosspollination of parts between vendor submissions.
http://soldiersystems.net/2017/10/06/crane-contaminates-surg-test-samples-by-crosspolinating-weapon-components-between-vendor-submissions-calls-on-offerors-for-new-samples/
You don't have to be anal about detail cleaning it after every use either. Google filthy 14. I use G96 but most any lube will work fine. Just stay away from frog lube which will gunk up and cause issues if your gun sits for a while.
I lube my BCG really good before shooting and wipe it down every 1k rounds or so. Tim a bore snake through every once in a while and never had an issue. Abuse the rifle a bit and you will see it has capable of more than you thought
Frog lube is good for cleaning I have found, works for Lube if shot right away, sucks for storage like said.. I use Lucas lube now.
I use AR pistols in 5.56 for home defense, after shooting them. Now have two un-shot AR9 pistols that might take that role after we test them (they were Wife's Idea after she borrowed one at last course). Both AR-15 based pistols were less than $1000, the Aero one close to that, the PSA close to $600. Both go bang every time, but the Aero is way better looking, if looks count.
Desert Trekker
01-14-19, 23:03
Note: "Ejecta" is the mass of projectile and powder. I mistakenly called it "Payload Mass" in my other post. The bullet is the payload but it's also part of the ejecta. The ejecta consists of the bullet and the gas.
The Oxford Dictionary defines recoil in the simplest of lay terms. As shooters striving to expand our knowledge, we have to realize there is more aspects to recoil than the dictionary covers. "Felt Recoil" and "Free Recoil" are inter-related but also significantly different. "Felt Recoil" is how the shooter perceives recoil. Free Recoil is how much recoil force is transferred to the shooter, the amount of force pushed into their shoulder. If a shooter wants to know "How do I reduce recoil?" the answer is always "Add mass to your firearm. Reduce ejecta mass. Reduce velocity." But if the shooter wants to change felt recoil, that another topic of discussion entirely.
Felt recoil is subjective and affected by any number of factors, such as buttpads, drop at comb, heel & toe angle, bore height over comb, operating system, type of clothing worn- you name it! Changes that soften recoil can actually increase recoil. A shooter might have a recoil pad installed that softens the recoil but lightens the rifle. More energy is transferred to the shooter, but it's softer and much more comfortable. Or the shooter might have a heavy brass buttplate installed. It adds mass to the rifle which decreases free recoil. But a brass buttplate is hard. Recoil transferred to the shooter is quicker, harder and all too often more painful. Less force to the shoulder but uncomfortably so.
Free recoil is objective and measurable and is affected by four specific factors- Muzzle Velocity, Ejecta Mass, Weapon Mass and the Constant Velocity of the Expanding Gas which is roughly 5700 fps. (The speed of the expanding gas is limited by bullet speed inside the bore but achieves full velocity once the bullet uncorks the muzzle. It's a significant part of recoil in high power rifle calibers.) These four factors are used to calculate how much is force pushed into the shoulder.
Taking mass away from the reciprocating parts reduces the overall mass of the firearm. Removing mass increases recoil- increases the force to the shoulder. It may feel softer, depending on how the speed of the reciprocating mass is tuned, but even by the definition found in the Oxford Dictionary, the result is more recoil.
Although it is disappointing that CRANE's evaluation lacks specifics on the rifles used for comparison, their measured data is consistent with other known tests. From CRANE: "Bolt speed is uniformly lower for mid-length gas systems when compared to carbine-length gas systems. Mid length bolt speed was 3.23 fps, or 22.6%, lower for unsuppressed fire." https://partner-mco-archive.s3.amazonaws.com/client_files/1527866983.pdf
A bolt/BCG moving significantly slower towards your shoulder will produce a mathematically lower recoil impulse. This is quantitative, not subjective. There is mathematically less recoil directed into your shoulder when shooting a mid length gas rifle compared to a carbine length gas rifle. This fact corresponds with the ubiquitous perception and opinion of those who have shot both types that the mid length is a softer shooting rifle.
Although it is disappointing that CRANE's evaluation lacks specifics on the rifles used for comparison, their measured data is consistent with other known tests. From CRANE: "Bolt speed is uniformly lower for mid-length gas systems when compared to carbine-length gas systems. Mid length bolt speed was 3.23 fps, or 22.6%, lower for unsuppressed fire." https://partner-mco-archive.s3.amazonaws.com/client_files/1527866983.pdf
A bolt/BCG moving significantly slower towards your shoulder will produce a mathematically lower recoil impulse. This is quantitative, not subjective. There is mathematically less recoil directed into your shoulder when shooting a mid length gas rifle compared to a carbine length gas rifle. This fact corresponds with the ubiquitous perception and opinion of those who have shot both types that the mid length is a softer shooting rifle.
A 7 pound rifle burning 24.5 grains of powder to propel a 55 grain bullet at 3000 feet per second will always produce 3.13 lbs of free recoil energy. That number doesn't change due to a different gas system.
I agree the mid-length applies the recoil energy over a longer period of time and the perceived recoil is reduced.
Andy
Desert Trekker
01-15-19, 08:19
A 7 pound rifle burning 24.5 grains of powder to propel a 55 grain bullet at 3000 feet per second will always produce 3.13 lbs of free recoil energy. That number doesn't change due to a different gas system.
I agree the mid-length applies the recoil energy over a longer period of time and the perceived recoil is reduced.
Andy
I'll utilize the powder and bullet speed example provided above to further illustrate the mathematically measurable difference in recoil between carbine and mid length gas systems. The perception of reduced recoil is due to this mathematically measurable reduction in energy directed into the shooter's shoulder.
Published tables of cartridge performance all correspond with the reality that measured energy is a product of velocity and mass. Using just one bullet weight, push the bullet faster and measured energy increases. Slow down the velocity of the same bullet and measured energy decreases.
The bolt carrier group (BCG) is thrust into the buffer tube after a cartridge is discharged. The quantifiable energy of the BCG is directed into the shooter's shoulder. Increased velocity of the BCG increases the measurable amount of energy the shooter receives in the shoulder. Referring back to CRANE's measurement, the BCG moves 22.6% slower in a mid length gas system compared to a carbine length gas system. This significant reduction in BCG speed factually, mathematically and perceptibly reduces recoil energy.
Is soldier systems actually doing the testing or just "reporting" on it? I read PDF of the actual report and the soldier systems guys conclusions seem completely incorrect.
"So far, Crane has put 30,400 rounds of M855A1 through three M4A1s equipped with 14.5″ cold hammer forged barrels and a mid-gas system with a gas block approximately 9.8″ from the bolt face.
They stated SOF M4A1s normally start to see accuracy degradation at around 6,000 rounds. But during testing of the mid-gas system, they’d hit 12,600 and still hadn’t seen any changes.
They also have only broken one bolt so far in testing, although I don’t think they’re ready to attribute the improved bolt performance to the mid-gas system.......
.........Although testing to 34,000 rounds isn’t yet complete, the conclusion is simple. Use of a mid-gas system significantly extends the life of the overall weapon system. It also offers increased performance over a carbine-length gas system."
This part.
The soldier system guys seem to read that as somehow the carbine guns barrel wore out much faster then the middy one, when in fact at over 12k round through each they saw no approfiable accuracy difference in either gun. So the fact that a midlength system "significantly" extends the life of the gun is completely false.
Here is a link to the military time article that has a link to the actual navsea report.
No significant difference is terminal velocity
No significant difference is muzzle velocity
No significant difference is precision or barrel erosion
People make way too big a deal over this carbine vs mid length thing.
https://www.militarytimes.com/news/your-military/2018/06/01/this-detailed-report-shows-which-m4-rifle-design-works-the-best/
I'll utilize the powder and bullet speed example provided above to further illustrate the mathematically measurable difference in recoil between carbine and mid length gas systems. The perception of reduced recoil is due to this mathematically measurable reduction in energy directed into the shooter's shoulder.
Published tables of cartridge performance all correspond with the reality that measured energy is a product of velocity and mass. Using just one bullet weight, push the bullet faster and measured energy increases. Slow down the velocity of the same bullet and measured energy decreases.
The bolt carrier group (BCG) is thrust into the buffer tube after a cartridge is discharged. The quantifiable energy of the BCG is directed into the shooter's shoulder. Increased velocity of the BCG increases the measurable amount of energy the shooter receives in the shoulder. Referring back to CRANE's measurement, the BCG moves 22.6% slower in a mid length gas system compared to a carbine length gas system. This significant reduction in BCG speed factually, mathematically and perceptibly reduces recoil energy.
I don’t mean to participate in the derailment of a thread, but you can’t “mathematically” eliminate energy. This is simple physics. The same energy is realeased firing the same cartridge regardless of what it is fired in. The midlength is simply allowing the recoil energy to be distributed over a longer amount of time giving the perception of less recoil....as was said in the post before. So instead of the rifle giving you a quick “punch” you get a shove. You could also achieve the same perception by making the rifle heavier, etc.
Still a good thing no doubt and would theoretically allow the shooter greater control and cause less stress on the rifle.
Like if you were to jump off a 6 foot platform and land with your knees locked vs bending them to deliver the energy slower.
You can always just build another. Nothing wrong with the colt as a first rifle. Use what you’ve learned and start stockpiling parts.
KISS mutt
https://uploads.tapatalk-cdn.com/20190106/b78a2ddb6565d03d0026d9b9795a216b.jpg
Oh man, does that carbine look NICE!
Desert Trekker
01-15-19, 11:55
I don’t mean to participate in the derailment of a thread, but you can’t “mathematically” eliminate energy. This is simple physics. The same energy is realeased firing the same cartridge regardless of what it is fired in. The midlength is simply allowing the recoil energy to be distributed over a longer amount of time giving the perception of less recoil....as was said in the post before. So instead of the rifle giving you a quick “punch” you get a shove. You could also achieve the same perception by making the rifle heavier, etc.
Still a good thing no doubt and would theoretically allow the shooter greater control and cause less stress on the rifle.
Like if you were to jump off a 6 foot platform and land with your knees locked vs bending them to deliver the energy slower.
Does an immobile bolt carrier group (BCG) exhibit any recoil energy? The answer is no. Does a BCG propelled at a speed of 3.23 feet per second (fps) as a result of the discharge of a cartridge exhibit recoil energy? The answer is yes. CRANE measured a 3.23 fps BCG speed decrease in the mid length gas system compared to a carbine length gas system. Gas pressure decreases with every inch of travel in the barrel. Reducing the amount of pressure applied to the BCG definitively reduces the amount of recoil, both measured and felt. The mid length gas port is further down the barrel from the location of a carbine length gas port, therefore it has less pressure available to send to the BCG. Pressure is what causes the BCG to recoil. Hence, mid length gas systems factually and perceptibly produce less recoil than carbine gas length systems.
The recoil energy of the BCG directed into your shoulder is measurable and tangible. The faster you move the BCG towards your shoulder the greater the amount of very real and measurable recoil transmitted to the shooter. This is neither subjective nor theoretical. BCGs move significantly faster in carbine length gas systems compared to mid length gas systems when firing identical cartridges in each.
Carbine length gas systems in fact produce more recoil than mid length gas systems. Science, math, and shooter perception all confirm this truth.
Does an immobile bolt carrier group (BCG) exhibit any recoil energy? The answer is no. Does a BCG propelled at a speed of 3.23 feet per second (fps) as a result of the discharge of a cartridge exhibit recoil energy? The answer is yes. CRANE measured a 3.23 fps BCG speed decrease in the mid length gas system compared to a carbine length gas system. Gas pressure decreases with every inch of travel in the barrel. Reducing the amount of pressure applied to the BCG definitively reduces the amount of recoil, both measured and felt. The mid length gas port is further down the barrel from the location of a carbine length gas port, therefore it has less pressure available to send to the BCG. Pressure is what causes the BCG to recoil. Hence, mid length gas systems factually and perceptibly produce less recoil than carbine gas length systems.
The recoil energy of the BCG directed into your shoulder is measurable and tangible. The faster you move the BCG towards your shoulder the greater the amount of very real and measurable recoil transmitted to the shooter. This is neither subjective nor theoretical. BCGs move significantly faster in carbine length gas systems compared to mid length gas systems when firing identical cartridges in each.
Carbine length gas systems in fact produce more recoil than mid length gas systems. Science, math, and shooter perception all confirm this truth.
You can not create or destroy energy and every action has an equal and opposite reaction. Physics 101
https://en.m.wikipedia.org/wiki/Conservation_of_energy
The bolt carrier group (BCG) is thrust into the buffer tube after a cartridge is discharged. The quantifiable energy of the BCG is directed into the shooter's shoulder. Increased velocity of the BCG increases the measurable amount of energy the shooter receives in the shoulder. Referring back to CRANE's measurement, the BCG moves 22.6% slower in a mid length gas system compared to a carbine length gas system. This significant reduction in BCG speed factually, mathematically and perceptibly reduces recoil energy.
Now were entering the realm of multiple recoil forces. Just as the rifle recoils to the rear from the force of the bullet being shoved forward, the rifle is also pushed forward by the force pushing the carrier to the rear. This transfers a part of the recoil energy to the carrier buffer and spring. When the carrier buffer and spring reach the end of their travel, the energy is once again transferred, back to the rifle and ultimately to the shooter. Moving the carrier faster doesn't create more recoil it just transfers more of the recoil energy to the carrier. If the carrier slowed to a stop over time recoil feels soft and more manageable. If brought to a sudden stop, such as when carrier momentum is more than the spring is designed to handle and slams into the back of the RE, recoil is sharp.
None of that recoil/counter recoil monkey business creates or destroys energy. It just stores and redistributes it.
Energy is the same.
Impulse is different.
As I stated in another thread, if you take the recoil in a big spike when the bcg bottoms out, its a higher impulse.
If you spread it out over the entire bolt cycle (extreme example is kac lmg), you get a long, soft impulse with little to no spike and feels like little recoil. Its like a soft butt pad- it doesnt reduce recoil, it lowers the impulse in your shoulder.
medicman29
01-15-19, 12:50
Like most everyone else has said, buy from a reputable company. colt. BCM. Daniel defense. Lube it up. buy lots of good training ammo and mags. go get lots of training, then practice. As much as you can. I've got all three of the above mentioned rifles, and they all run really well. I will say that my BCM rifles are my favorites, and I have several thousand rounds through a couple of them each. One has never had a failure I didnt induce on purpose. The other, the only failures came during a high volume class when the independence ammo I was shooting was blowing the primers out, and caused several failures. Not sure why, because I ran a case of the same ammo through that rifle at a previous class with no problems. My DD and colts don't have enough through them at this point for me to say one way or the other, but they've been reliable up to this point. I will also say that I feel that the midlengths seem to shoot softer, subjectively.
Desert Trekker
01-15-19, 12:52
You can not create or destroy energy and every action has an equal and opposite reaction. Physics 101
https://en.m.wikipedia.org/wiki/Conservation_of_energy
The energy released from discharging identical cartridges will be identical within tiny fractions of differences due to the impossibility of everything being perfectly exact among multiple examples.
If these cartridges were discharged in the open air with a bolt carrier group (BCG) two inches behind the cartridges, how much recoil would you expect the BCG to exhibit under these circumstances? (Never attempt this as it would be unsafe)
Now if these cartridges were discharged in a carbine, would you anticipate more recoil of the BCG under these circumstances? Of course there will be massively more recoil in this scenario. The same amount of energy is present, yet more of that energy is directed to the BCG when fired in the carbine. The mid length gas system transmits less energy to the BCG then does a carbine length gas system. Energy is not recoil. The manner in which energy is directed will increase or decrease recoil.
Unless we are to redefine the universally accepted meaning of recoil, mid length gas systems factually produce less recoil than carbine length gas systems. When discharging a cartridge within a rifle recoil is typically understood to be the force transmitted rearward.
Desert Trekker
01-15-19, 13:05
For the legal CYA, NEVER, repeat, NEVER discharge a cartridge in the open air or in any way other than the manufacturers approve of and/or recommend. The previous post comments were provided to make a mental visual point, NOT to suggest physically attempting any actions.
Desert Trekker
01-15-19, 14:43
Now were entering the realm of multiple recoil forces. Just as the rifle recoils to the rear from the force of the bullet being shoved forward, the rifle is also pushed forward by the force pushing the carrier to the rear. This transfers a part of the recoil energy to the carrier buffer and spring. When the carrier buffer and spring reach the end of their travel, the energy is once again transferred, back to the rifle and ultimately to the shooter. Moving the carrier faster doesn't create more recoil it just transfers more of the recoil energy to the carrier. If the carrier slowed to a stop over time recoil feels soft and more manageable. If brought to a sudden stop, such as when carrier momentum is more than the spring is designed to handle and slams into the back of the RE, recoil is sharp.
None of that recoil/counter recoil monkey business creates or destroys energy. It just stores and redistributes it.
Every action has an equal and opposite reaction. This is an undeniably proven fact.
Recoil in a rifle is rearward thrust. The recoil energy from the thrust of a BCG is transmitted to your shoulder before the opposite reaction occurs. The push and subsequent pull are not simultaneous.
An increase in BCG speed increases recoil energy transmitted directly to the shooter, and Newton's Third Law does not reduce the force received by the shooter because the opposite reaction occurs after the recoil energy impacts the shooter.
Hence, a mid length gas system shown to move the BCG 22.6 % slower than a carbine length gas system will produce a quantifiable and perceptible reduction in recoil.
bobbytucson
01-17-19, 03:28
I've been deliberating over this issue for months. I bought a Colt 6920 as my main go-to rifle in 2016 specifically because I thought it was the most reliable AR15 I could buy. It has never jammed, but several months ago I started reading about the improved reliability of midlength gas systems and am doubting my purchase. In short, I want the most reliable AR15 I can get. I'm not interested in the bells and whistles of the KAC or URGI, but I am interested in maximum reliability. I'd rather not have to spend $2500 on just the rifle and would prefer something basic, but I will save up for that if that's what it takes.
What is the most reliable AR15? Do you have to go to KAC with the expensive features I don't want (such as the URX rail, flash hider, etc) to get the most reliable rifle?
(I also have a Colt AR15A4, but I'm starting to agree that it's a bit long for indoors use)
Something I've been considering was re-barreling my 6920 with the same barrel the URGI uses by Daniel Defense, but I'm not sure if that's an efficient option.
A short, accurate, and serious answer to your long question is this, buy a SIONICS. Its not as pricey as bcm and daniel but every bit as extremely properly built with quality material geared towards duty & fighting, and with that money you will save, you can reinvest in ammo & training. Sionics is serious suff built by some of the best armorors in the country.
Doc Safari
01-17-19, 09:11
've been deliberating over this issue for months. I bought a Colt 6920 as my main go-to rifle in 2016 specifically because I thought it was the most reliable AR15 I could buy. It has never jammed, but several months ago I started reading about the improved reliability of midlength gas systems and am doubting my purchase. In short, I want the most reliable AR15 I can get. I'm not interested in the bells and whistles of the KAC or URGI, but I am interested in maximum reliability. I'd rather not have to spend $2500 on just the rifle and would prefer something basic, but I will save up for that if that's what it takes.
What is the most reliable AR15? Do you have to go to KAC with the expensive features I don't want (such as the URX rail, flash hider, etc) to get the most reliable rifle?
(I also have a Colt AR15A4, but I'm starting to agree that it's a bit long for indoors use)
Something I've been considering was re-barreling my 6920 with the same barrel the URGI uses by Daniel Defense, but I'm not sure if that's an efficient option.
Frankly, I dabbled with a BCM 14.5 pinned mid-length ten years ago, and it quickly went to consignment after firing it only a handful of times. Why? It was utterly unreliable with anything but full horse 5.56 ammo. Being a civilian subject to the whims of supply and Wal-Mart, I have to shoot regular .223 a large part of the time. I emailed BCM as to why it was unreliable with .223, and they suggested I install a carbine buffer instead of the H buffer. Problem solved. That got me thinking: in a SHTF situation I don't want to have to switch buffers depending on whether I'm shooting 5.56 or .223, especially since I may have both in loaded magazines. I know it's a sample of one but since all my carbine gassed AR's are 100% with either flavor of ammo, I decided mid-length was just too finicky and I got rid of the rifle.
On another point, if you watch some of smallarmssolutions videos on YouTube he is of the contention that the bolt breakage problem in carbines was largely due to excessive firing schedules (i.e. trying to use an M4 as a SAW), and that Colt eventually solved the problem in the mid-2000's by tweaking the heat treating of their bolts. I can't link to a specific video since it's been a while since I watched them, but I think it's his history of the M4 videos.
Frankly, I dabbled with a BCM 14.5 pinned mid-length ten years ago, and it quickly went to consignment after firing it only a handful of times. Why? It was utterly unreliable with anything but full horse 5.56 ammo. Being a civilian subject to the whims of supply and Wal-Mart, I have to shoot regular .223 a large part of the time. I emailed BCM as to why it was unreliable with .223, and they suggested I install a carbine buffer instead of the H buffer. Problem solved. That got me thinking: in a SHTF situation I don't want to have to switch buffers depending on whether I'm shooting 5.56 or .223, especially since I may have both in loaded magazines. I know it's a sample of one but since all my carbine gassed AR's are 100% with either flavor of ammo, I decided mid-length was just too finicky and I got rid of the rifle.
On another point, if you watch some of smallarmssolutions videos on YouTube he is of the contention that the bolt breakage problem in carbines was largely due to excessive firing schedules (i.e. trying to use an M4 as a SAW), and that Colt eventually solved the problem in the mid-2000's by tweaking the heat treating of their bolts. I can't link to a specific video since it's been a while since I watched them, but I think it's his history of the M4 videos.
That’s super weird, I almost always shoot .223 and have never had an issue with the even the stock buffer setup. That being said, you wouldn’t have had to switch back to an H buffer when going to 5.56, it would’ve just been a little more over-gassed.
Sent from my iPhone using Tapatalk
Doc Safari
01-17-19, 09:48
That’s super weird, I almost always shoot .223 and have never had an issue with the even the stock buffer setup. That being said, you wouldn’t have had to switch back to an H buffer when going to 5.56, it would’ve just been a little more over-gassed.
I do have to add one thing: I said "Wal-Mart" in my last post but thinking about it, back in those days I shot PMC mostly. I still have several ammo cans full of it.
I wasn't worried about felt recoil either but it gets us back to parts durability. If one of the main reasons to have a mid-length is to promote longer bolt life, then switching buffers creates another issue. If you leave the carbine buffer in during full power 5.56 shooting, does that increase wear and tear on the parts? In other words, if you leave the lower power buffer in for reliability have you de facto converted your mid-length to a carbine?
I honestly don't know if other mid-lengths are that finicky, but mine definitely preferred full power 5.56 with the H buffer. I've never had a carbine hiccup on any ammo (and I don't shoot steel case by the way).
I chalked it up to "when in doubt...." and the mid-length got sold.
I know a lot of people consider PMC crap ammo, but it was always reliable in all but that one weapon. Once again: since I'm subject to the whims of supply I want to shoot 100% reliably with whatever I get.
Doc, I keep thinking that, instead of "Doc Safari" you should have changed your name to "Doc Tari". Rolls of the tongue easier and- well, because "Daktari", you know?
I do have to add one thing: I said "Wal-Mart" in my last post but thinking about it, back in those days I shot PMC mostly. I still have several ammo cans full of it.
I wasn't worried about felt recoil either but it gets us back to parts durability. If one of the main reasons to have a mid-length is to promote longer bolt life, then switching buffers creates another issue. If you leave the carbine buffer in during full power 5.56 shooting, does that increase wear and tear on the parts? In other words, if you leave the lower power buffer in for reliability have you de facto converted your mid-length to a carbine?
I honestly don't know if other mid-lengths are that finicky, but mine definitely preferred full power 5.56 with the H buffer. I've never had a carbine hiccup on any ammo (and I don't shoot steel case by the way).
I chalked it up to "when in doubt...." and the mid-length got sold.
I know a lot of people consider PMC crap ammo, but it was always reliable in all but that one weapon. Once again: since I'm subject to the whims of supply I want to shoot 100% reliably with whatever I get.
Using 5.56 pressure ammo in your old BCM middy with the carbine buffer isn't any worse than using standard (5.56) ammo in any upper that runs on both low pressure and standard pressure.
Doc Safari
01-17-19, 10:23
Doc, I keep thinking that, instead of "Doc Safari" you should have changed your name to "Doc Tari". Rolls of the tongue easier and- well, because "Daktari", you know?
I actually thought about that, but most people don't have a clue what Daktari was.
Frankly, I dabbled with a BCM 14.5 pinned mid-length ten years ago, and it quickly went to consignment after firing it only a handful of times. Why? It was utterly unreliable with anything but full horse 5.56 ammo.
This is a poor position to take based on a sample of one. That one being known as "the softest shooting middy" = the smallest gas port.
You compound this by using a heavier buffer than the manufacturer recommends.
Then shoot ammo that ammo had a well known problem in longer gas system barrels. There was a time PMC was known to fail pretty regularly in a 20" rifle. They used a faster than normal burn rate powder, so port pressure dropped faster at longer gas system lengths.
While I don't expect everyone to know everything, these were known problems back then and could have been researched. I believe you should rethink your negativity towards the midlength and give it another try sometime.
Doc Safari
01-17-19, 11:47
This is a poor position to take based on a sample of one. That one being known as "the softest shooting middy" = the smallest gas port.
You compound this by using a heavier buffer than the manufacturer recommends.
Then shoot ammo that ammo had a well known problem in longer gas system barrels. There was a time PMC was known to fail pretty regularly in a 20" rifle. They used a faster than normal burn rate powder, so port pressure dropped faster at longer gas system lengths.
While I don't expect everyone to know everything, these were known problems back then and could have been researched. I believe you should rethink your negativity towards the midlength and give it another try sometime.
The "heavier" buffer was supplied by BCM with the rifle as it shipped from the factory, so I guess that qualifies as "what the manufacturer recommends." It was only in an email did they suggest switching to the carbine buffer.
If I can't use readily available ammo (PMC in this case), then the rifle is of no use to me. I draw the line at steel-cased, but when I bought my carbines in 2010 PMC was readily available and affordable, not so some other brands at that time.
Mid-length is of no consequence to me. No further research was necessary in my book. It failed according to parameters that I deal with every day. Whatever is de rigeur among "operators" or mid-length fans is of no consequence to me.
Reliability was simply unacceptable in the mid-length when it was 100% using carbine gas.
End of story with me and the mid-length.
Do what you like, but mid-length is dead to me.
...mid-length is dead to me.
Carbine, middy, rifle- gas system length makes less difference than port diameter.
However, the BCM you had running with a CAR buffer shooting 5.56 was probably a little less violent than shooting 5.56 in a carbine system tuned to run low pressure ammo, like PMC.
SouthwestAviator
01-17-19, 14:17
One of my shooting buddies has a BCM midlength 14.5" that also will not run .223 pressure ammo in factory-stock configuration.
Doc Safari
01-17-19, 14:20
Carbine, middy, rifle- gas system length makes less difference than port diameter.
However, the BCM you had running with a CAR buffer shooting 5.56 was probably a little less violent than shooting 5.56 in a carbine system tuned to run low pressure ammo, like PMC.
I never really noticed an appreciable difference in recoil shooting mid-length vs carbine--as opposed to the recoil difference between an AK and an AR, for example. IIRC I only shot .223 in that mid-length (since that's what lead to the controversy). All I know is that all my carbine-gassed M4's, whether BCM or Colt, ate low pressure .223 and 5.56 with no hiccups. Over-gassed? Maybe. But in a SHTF situation where you have to make do with what you've got, I'd rather have 100% reliability than softer recoil or less battering of components.
Even though I had a sample of one mid-length, that ONE was unreliable with commercial .223 using the factory setup, and that concerned me. It's ten years later and maybe specs have been tweaked a gazillion times since then, but my experience was that a gun running carbine gas ate everything I fed it, and the mid-length did not.
For those that like or prefer the mid-length: more power to ya
If your mid-length satisfies you, rock on. As a SHTF weapon I'd never trust one, though, knowing it didn't like admittedly second-rate ammo when other AR's in my stash gobbled it up just fine.
To reiterate: I even stopped worrying about parts wear after watching the videos from smallarmssolutions on YouTube where he says that the bolt breakage problem was a fluke in Colt's manufacturing and a misuse of M4's as SAW's rather than a design flaw in carbine gas per se.
If someone wants to defend mid-length: I would love to read how smallarmssolutions is full of shit and why.
I never really noticed an appreciable difference in recoil shooting mid-length vs carbine--as opposed to the recoil difference between an AK and an AR, for example. IIRC I only shot .223 in that mid-length (since that's what lead to the controversy). All I know is that all my carbine-gassed M4's, whether BCM or Colt, ate low pressure .223 and 5.56 with no hiccups. Over-gassed? Maybe. But in a SHTF situation where you have to make do with what you've got, I'd rather have 100% reliability than softer recoil or less battering of components.
Even though I had a sample of one mid-length, that ONE was unreliable with commercial .223 using the factory setup, and that concerned me. It's ten years later and maybe specs have been tweaked a gazillion times since then, but my experience was that a gun running carbine gas ate everything I fed it, and the mid-length did not.
For those that like or prefer the mid-length: more power to ya
If your mid-length satisfies you, rock on. As a SHTF weapon I'd never trust one, though, knowing it didn't like admittedly second-rate ammo when other AR's in my stash gobbled it up just fine.
To reiterate: I even stopped worrying about parts wear after watching the videos from smallarmssolutions on YouTube where he says that the bolt breakage problem was a fluke in Colt's manufacturing and a misuse of M4's as SAW's rather than a design flaw in carbine gas per se.
If someone wants to defend mid-length: I would love to read how smallarmssolutions is full of shit and why.
Actually, I thought that guy was full of shit.
Doc Safari
01-17-19, 14:44
Actually, I thought that guy was full of shit.
But why? Give us some feedback. I'm open to hearing an opposing view.
SouthwestAviator
01-17-19, 15:07
I've heard Chris Bartocci of SmallArmsSolutions say he prefers midlength on a few occasions. I believe the title of one video that he mentions it in is called something like "If I could only have one..." and he says that the only thing he'd change on his "go-to" LMT standard AR is making it a mid-length gas system. I do recall him saying that the problems with bolts breaking with M4s was caused by a combination of QC issues on Colt's part and users treating them like SAWs, though. I've read that was the case from somewhere else too, but I can't remember where at the moment. I'm not saying SmallArmsSolutions is or is not full of shit. I have no opinion either way with that guy. A couple of things he's said has made me raise an eyebrow (mostly on things unrelated to AR's, such as his reasoning for his preference of 124gr +p 9mm over 147gr).
I've stocked up enough Colt complete BCGs to where I can afford to just throw in a new BCG every 3-4k rounds and not have to worry about parts breakage. The only thing that has made me consider switching to midlength is increased reliability, but that seems to only be demonstrated with grossly overpressured ammo like M855A1 (and even in the Crane test demonstrating that, the MRBS figures for the midlength weren't that impressive. Earlier Army tests showing the carbine-gas M4 going 3600 Mean Rounds Between Stoppages with regular M855 beat it out.)
But why? Give us some feedback. I'm open to hearing an opposing view.
I have no idea, I don't remember where I heard it. Was more saying to see if anyone else had more details. Not at all helpful, I know.
Doc Safari
01-17-19, 15:14
I've heard Chris Bartocci of SmallArmsSolutions say he prefers midlength on a few occasions. I believe the title of one video that he mentions it in is called something like "If I could only have one..." and he says that the only thing he'd change on his "go-to" LMT standard AR is making it a mid-length gas system. I do recall him saying that the problems with bolts breaking with M4s was caused by a combination of QC issues on Colt's part and users treating them like SAWs, though. I've read that was the case from somewhere else too, but I can't remember where at the moment. I'm not saying SmallArmsSolutions is or is not full of shit. I have no opinion either way with that guy. A couple of things he's said has made me raise an eyebrow.
He did do a video showing his perfect rifle. It's very interesting. And yes, it was a mid-length if I recall.
I've stocked up enough Colt complete BCGs to where I can afford to just throw in a new BCG every 3-4k rounds and not have to worry about parts breakage. The only thing that has made me consider switching to midlength is increased reliability, but that seems to only be demonstrated with grossly overpressured ammo like M855A1 (and even in the Crane test demonstrating that, the MRBS figures for the midlength weren't that impressive. Earlier Army tests showing the carbine-gas M4 going 3600 Mean Rounds Between Stoppages with regular M855 beat it out.)
There's a member here, and I can't remember who--that changes cam pins every few thousand rounds and that seems to help with bolt breakage. Or is it just that he does it as PM and has never actually experienced much bolt breakage anyway? I can't remember which.
This isn't to argue or try and change your mind Doc, just to give others reading all the facts I know.
https://www.m4carbine.net/showthread.php?7757-interesting-PMC-ammo-problem
I think BCM 14.5" mids were over represented in short stroking at that time, with PMC and a few other bottom shelf ammo makes more often than not being involved. I think it's likely the port size got increased a little and PMC got a bit better, because that trend didn't last very long.
My more recent BCM 14.5" mid runs more recent PMC with an H2 buffer.
Doc Safari
01-17-19, 17:22
This isn't to argue or try and change your mind Doc, just to give others reading all the facts I know.
https://www.m4carbine.net/showthread.php?7757-interesting-PMC-ammo-problem
I think BCM 14.5" mids were over represented in short stroking at that time, with PMC and a few other bottom shelf ammo makes more often than not being involved. I think it's likely the port size got increased a little and PMC got a bit better, because that trend didn't last very long.
My more recent BCM 14.5" mid runs more recent PMC with an H2 buffer.
So I just got unlucky? Wouldn't surprise me. That thread was posted about three years before I got back into AR's, and since BCM answered my email with the solution I would never have bothered to do another search.
Disclaimer- non-expert opinion.
556 and 223 are 2 different rounds, which I believe leads to so may “problems” with ARs.
You either tailor it to 556, and risk 223 unreliability, or tailor it to 223 and PM parts (bolts mainly) sooner.
SouthwestAviator
01-18-19, 15:12
Disclaimer- non-expert opinion.
556 and 223 are 2 different rounds, which I believe leads to so may “problems” with ARs.
You either tailor it to 556, and risk 223 unreliability, or tailor it to 223 and PM parts (bolts mainly) sooner.
Makes sense, though I think carbine-length gas ARs with an H buffer and .063" gas port (ie. standard M4 configuration) will run low powered .223 thru 5.56 pressure ammo. My 6920 doesn't differentiate between 5.56 and .223 functionality-wise. It just eats everything I feed it.
(and even in the Crane test demonstrating that, the MRBS figures for the midlength weren't that impressive. Earlier Army tests showing the carbine-gas M4 going 3600 Mean Rounds Between Stoppages with regular M855 beat it out.)
Maybe I'm miss-interpreting what I read:
So far, Crane has put 30,400 rounds of M855A1 through three M4A1s equipped with 14.5″ cold hammer forged barrels and a mid-gas system with a gas block approximately 9.8″ from the bolt face.
They stated SOF M4A1s normally start to see accuracy degradation at around 6,000 rounds. But during testing of the mid-gas system, they’d hit 12,600 and still hadn’t seen any changes.
The mid-length gas systems experienced a total of 30 malfunctions, while the carbine-length gas systems experienced more than double that at 65 malfunctions. Additionally, the carbine-length gas system suffered 13 unserviceable parts, while the mid-length gas system only suffered 9 unserviceable parts.
Mean rounds between failures (MRBF) Carbine: 581.5 Mid-Length: 1260.0
Granted, 581 rounds between failures is pretty good, but dang, 1260 is twice as good.
Doc Safari
01-18-19, 15:40
Maybe I'm miss-interpreting what I read:
So far, Crane has put 30,400 rounds of M855A1 through three M4A1s equipped with 14.5″ cold hammer forged barrels and a mid-gas system with a gas block approximately 9.8″ from the bolt face.
They stated SOF M4A1s normally start to see accuracy degradation at around 6,000 rounds. But during testing of the mid-gas system, they’d hit 12,600 and still hadn’t seen any changes.
The mid-length gas systems experienced a total of 30 malfunctions, while the carbine-length gas systems experienced more than double that at 65 malfunctions. Additionally, the carbine-length gas system suffered 13 unserviceable parts, while the mid-length gas system only suffered 9 unserviceable parts.
Mean rounds between failures (MRBF) Carbine: 581.5 Mid-Length: 1260.0
Granted, 581 rounds between failures is pretty good, but dang, 1260 is twice as good.
What was the firing schedule? Were they shooting on constant full auto?
SouthwestAviator
01-18-19, 16:01
Maybe I'm miss-interpreting what I read:
So far, Crane has put 30,400 rounds of M855A1 through three M4A1s equipped with 14.5″ cold hammer forged barrels and a mid-gas system with a gas block approximately 9.8″ from the bolt face.
They stated SOF M4A1s normally start to see accuracy degradation at around 6,000 rounds. But during testing of the mid-gas system, they’d hit 12,600 and still hadn’t seen any changes.
The mid-length gas systems experienced a total of 30 malfunctions, while the carbine-length gas systems experienced more than double that at 65 malfunctions. Additionally, the carbine-length gas system suffered 13 unserviceable parts, while the mid-length gas system only suffered 9 unserviceable parts.
Mean rounds between failures (MRBF) Carbine: 581.5 Mid-Length: 1260.0
Granted, 581 rounds between failures is pretty good, but dang, 1260 is twice as good.
Maybe it's a difference of opinion, but I don't think 581 or 1260 is a good number between failures/stoppages. Especially when the Army said in 2009 that the current MRBS for the M4 Carbine was over 3600 (Source: https://www.peosoldier.army.mil/docs/WeaponsReliabilityInformationPaper-Oct%2009.pdf ). This was using M855.
The demonstrated current reliability is over 3600 MRBS as a result of our continuous improvement program
Slide 10 on this Project Manager Soldier Weapons briefing ( https://ndiastorage.blob.core.usgovcloudapi.net/ndia/2011/smallarms/PM_Soldier_Weapons_NDIA.pdf ) references a test in which the MRBS of the M4 Carbine was demonstrated to be 3,592 using M855. This seems to coincide with the Army's requirement for the Individual Carbine to beat that MRBS specifically (but the adoption of M855A1 threw a wrench in all that imo).
Personally I only want to trust something with at least 2k between stoppages. My pistols easily do this, and I'd expect a military-grade rifle to do at least as well. I do not know what magazines the Crane midlength test used, or how the firing schedule was broken up. The only explanation I can think of for the discrepancy between the Army's numbers and the Crane test's is that those Army tests were using M855, and the M855A1 has been known to cause less reliability. I suspect that the midlength is more reliable with M855A1 than the carbine, but with non-grossly-overpressure ammo the difference in reliability is much smaller. In addition, I suspect that the carbine will be more reliable than the midlength with low pressure .223. That's speculation on my part, though.
Why are we still debating this nonsense?
Why are we still debating this nonsense?
You answered you own question 10 pages ago, "You are overthinking this shit massively".
Lol, Andy. That was a great analogy!
It explains alot of the reasons I build my guns up.
Ever since I drove a modified bmw M car with 700hp at 140 mph, I've had a hard time getting into my wife's ford again. Its all very relative. Ever since I built out a kac and dd carbines with suppressors, et al... i dont even know what a basic AR15 is anymore (:
(I also have a Colt AR15A4, but I'm starting to agree that it's a bit long for indoors use) I won't comment on your colt 6920 other than to say there's nothing wrong with that choice
As far as your A4 being "a bit long for indoors use" I agree. Buy a pistol or if you want build or buy an AR pistol in a pistol caliber. But don't do what I did for my first ever build and get a AR 15 pistol with a 7.5in barrel. Sure it's really handy in tight spaces but if you ever pull the trigger inside a small enclosed area you may never hear again. A 10-11.5 in barrel is better but to be honest if you have any neighbors close by I would stick with a pistol caliber so if you need to neutralize a threat you don't kill your neighbors at the same time.
Hell I've got 2 Stag Arms and 1 Windham Weaponry and I've got zero qualms with using any one of them in the field or for personal defense. Nominal mods to furniture only, good optics and mags and lots of rounds down range with no malfunctions of any kind
Sent from my SM-N950U using Tapatalk
The simple answer, the most reliable one for self defense is one that you’ve put a bunch of rounds through and know that it works. I realize that sounds like some kind of snarky answer but it’s true. I’ve been working as a gunsmith for about a decade and a half and I’ve seen AR that cost thousands of dollars not funcruon and ARs that cost a few hundred run like a well oiled sewing machine.
The reliability issue is much more likely to come up if it’s not maintained properly rather than how much it costs.
Man...a lot going on in this thread. Good and bad...
Shoot the gun as-is. Get a reliable red dot if you choose, but definitely run a good light and sling that works for you. Train, train, train, and when the barrel starts to keyhole several thousand rounds from now replace it with a mid-length from DD, BCM, or any true mil-spec manufacturer. Probably a good idea to replace the bolt at that point too.
ARs run fine a bit dirty as long as you keep it well lubed. That said, I’m pretty anal about cleaning mine after each use. Many ways to clean your weapon, and you’ll get as many opinions as there are members of this site re: the “right” way to do it. I typically just use Hoppes #9 and Birchwood Casey gun scrubber to clean, then a very light machine oil with teflon as a lube. Will use Lucas gun lube if I’m planning extended range sessions, or MPro-7 if it’s going back into the safe for an extended period.
YMMV.
Go gentle into that good night,
Old age should burn and rave at close of day;
Rage, rage against the dying of the light.
Though wise men at their end know dark is right,
Because their words had forked no lightning they
Go gentle into that good night.
Good men, the last wave by, crying how bright
Their frail deeds might have danced in a green bay,
Rage, rage against the dying of the light.
Wild men who caught and sang the sun in flight,
And learn, too late, they grieved it on its way,
Go gentle into that good night.
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