View Full Version : Carbine vs Mid
Is a Carbine system going to wear any faster than the Mid Lenght sytem?I guess I am asking will I ever wear it out shooting about 1000 rounds a year?I have read on other sites were its seems to be biased for the Mid lenght.
Jason
LowSpeed_HighDrag
11-07-10, 14:07
Yes, the carbine system will wear "faster" than a middy system. Will you notice it? Not likely. A carbine gas system from a good mfg will last you a very long time.
I will add, "bias" towards the mid length system is like some one saying, "fitness experts are biased because they say more excercise can lead to a longer life." The fact is a mid length gas system is not as rough on internals, but that does not mean a carbine will automatically fail you.
The reality is, there ARE quality mid lengths to choose from.
With that in mind, there's no reason to bother with the carbine system at all. It's an example of poor engineering.
With that in mind, there's no reason to bother with the carbine system at all. It's an example of poor engineering.
Let's not get too carried away with the hyperbole. That "poor engineering" has enabled millions of rounds sent downrange at and into bad guys. It has done, and will continue to do, a tremendous job.
a thousand rounds a year... you probably wont ever wear out any rifle, carbine or midlength, shooting a 1000 rounds a year.
Let's not get too carried away with the hyperbole. That "poor engineering" has enabled millions of rounds sent downrange at and into bad guys. It has done, and will continue to do, a tremendous job.
The OP is a consumer who can pick and choose what he wants.
It would be wise to choose the path of least resistance.
variablebinary
11-07-10, 17:57
The carbine length gas system puts more pressure on parts, so yeah, you could say it wears faster.
To what extent, who knows. Your typical off the rack M4 will digest a hell of a lot rounds before giving up up the ghost. Same for the middy
More than anything else, I would say it is preference. I could go either way personally. Both are sound if you buy right.
jumbopanda
11-07-10, 19:38
You're not likely to wear out either one, but mid-lengths are just a product of better engineering. The biggest advantage of having a mid-length is that their recoil is softer than that of carbines. You also get a longer sight radius.
I'm an owner of a carbine length gas system rifle...I shoot 1000 rounds a month. Coming up for about 18 months of that now, and its not worn out yet, so at 1000 rounds a year, I think you'll be good for a while... ;)
That said, if you don't already own a carbine lengthed rifle - as the others have said, there really is no point in ever choosing that over a middy (in a 14.5 or 16 inch barrel....shorties obviously excepted). When I have to rebarrel mine, I will be putting a mid length on there.
ForTehNguyen
11-08-10, 08:37
even if you dont get near the wear limits of either, 2 more inches of handguard is a heck of a lot more comfortable.
Yes, the carbine system will wear "faster" than a middy system. Will you notice it? Not likely. A carbine gas system from a good mfg will last you a very long time.
I will add, "bias" towards the mid length system is like some one saying, "fitness experts are biased because they say more excercise can lead to a longer life." The fact is a mid length gas system is not as rough on internals, but that does not mean a carbine will automatically fail you.
I'm still waiting for the testing that demonstrates this. It's one of those things that's been said enough, and seems logical enough with a basic understanding of the system, but that there has been no documented evidence that I'm aware of.
Let's not get too carried away with the hyperbole. That "poor engineering" has enabled millions of rounds sent downrange at and into bad guys. It has done, and will continue to do, a tremendous job.
I was just about to say THIS.
There are hundreds of thousands of carbines out there which has proven themselves under the harshest conditions.
Is a middy better...yes...noticeably...maybe...but like myself and others have stated in carbine -v- middy threads before, has the quantitative testing been done to determine if there is a statistically significant difference? At least not yet.
It will be a helluva long time, if ever, before middies out number carbines.
I'm an owner of a carbine length gas system rifle...I shoot 1000 rounds a month. Coming up for about 18 months of that now, and its not worn out yet, so at 1000 rounds a year, I think you'll be good for a while... ;)
That said, if you don't already own a carbine lengthed rifle - as the others have said, there really is no point in ever choosing that over a middy (in a 14.5 or 16 inch barrel....shorties obviously excepted). When I have to rebarrel mine, I will be putting a mid length on there.
Yes, there is no reason to rebarrel just to go midlength.
In 20 or so years (@1,000 rnds/yr) when it's time for you to start thinking about a new barrel, the whole middy vs. carbine thing will have sorted itself out...maybe.
Let's not get too carried away with the hyperbole. That "poor engineering" has enabled millions of rounds sent downrange at and into bad guys. It has done, and will continue to do, a tremendous job.
That's a good point. Are there any middies in the Military? Are any units deploying any middies?
I'm still waiting for the testing that demonstrates this. It's one of those things that's been said enough, and seems logical enough with a basic understanding of the system, but that there has been no documented evidence that I'm aware of.
I think it's pretty easy to demonstrate the principles that support the concept - shorter dwell, delayed extraction, lower gas volume, lower bolt speed, distance and arc of ejected cases, etc., can be observed and measured in a midlength. given these factors it's logical to assume lower stress to the parts of the mechanism.
I know you are asking for empirical testing that compares something like a large quantity of middies vs. CAR firing same ammo in same conditions and evaluating failures but do we actually have to do that to be able to infer, scientifically, that one is more longterm reliable than the other?
I mean, no one really knows what the atmosphere of Saturn is made up of but through radiographic spectral analysis, we can take a pretty good guess, right? ;)
That's a good point. Are there any middies in the Military? Are any units deploying any middies?
I don't believe so, but they also aren't using 16" barrels on carbine gas systems either...
I think it's pretty easy to demonstrate the principles that support the concept - shorter dwell, delayed extraction, lower gas volume, lower bolt speed, distance and arc of ejected cases, etc., can be observed and measured in a midlength. given these factors it's logical to assume lower stress to the parts of the mechanism.
I know you are asking for empirical testing that compares something like a large quantity of middies vs. CAR firing same ammo in same conditions and evaluating failures but do we actually have to do that to be able to infer, scientifically, that one is more longterm reliable than the other?
I mean, no one really knows what the atmosphere of Saturn is made up of but through radiographic spectral analysis, we can take a pretty good guess, right? ;)
I didn't really want to turn this into yet another science debate, I just wanted to point out that things that people have a tendency of going around spouting as if ffact are too often things that they are only repeating.
and yes, I'd still like to see someone quantify all these claims in some way other than grainy high-speed video.
and I'd also like to know if "stress on the parts" is considered to be high enough to be cumulative and if that cumulative stress really matters in any meaningful way. After the whole debacle of the HPT debate it's clear that many people have just enough knowledge of things to be dangerous and perhas too much to be willing to ask questions.
I have a POS Bushmaster 14.5" carbean upper with like 30k rounds through it. It still head spaces ok, and will hold under 2" groups at 100 as of last weekend.
If you're shooting only 1000 per year... you'll get at least 30 years useage out of it.... give or take. :p
glockkid88
11-08-10, 20:34
This thread is a big relief to me. I just purchased a ddm4 carbine about 2 months ago. I was sure that I had bought the best carbine in my price range until I started seeing the craze for midlength systems. I found thinking that I may have made the wrong decision and maybe should have bought a midlength carbine. I am new to the rifles and am trying not to get too caught up in the newest coolest shit craze. I almost bought a new lower to build a midlenght m4 recently but now I think that the money would be better spent on ammo and learning to shoot the carbine length system I have. I will probably shoot no more than 5k next year and I am sure the ddm4 will serve me well.
This thread is a big relief to me.
The middies are nice and shoot a bit smoother.... but not worth dumping a perfectly good carbean over. You just build another gun and go from there.
RogerinTPA
11-08-10, 21:21
This thread is a big relief to me. I just purchased a ddm4 carbine about 2 months ago. I was sure that I had bought the best carbine in my price range until I started seeing the craze for midlength systems. I found thinking that I may have made the wrong decision and maybe should have bought a midlength carbine. I am new to the rifles and am trying not to get too caught up in the newest coolest shit craze. I almost bought a new lower to build a midlenght m4 recently but now I think that the money would be better spent on ammo and learning to shoot the carbine length system I have. I will probably shoot no more than 5k next year and I am sure the ddm4 will serve me well.
Wise choice. I have two of each and enjoy shooting both but I do prefer the mid-lengths, but mostly for more rail for hand placement. Throw a Battlecomp on her and you won't regret it.
fivefivesix
11-08-10, 21:51
ive got just over 500 rounds in a day thru my dd carbine with not one failure. mixed ammo wolf and brass cased fedral
RogerinTPA
11-08-10, 21:58
ive got just over 500 rounds in a day thru my dd carbine with not one failure. mixed ammo wolf and brass cased fedral
Careful with that combo. Mixing steel and brass ammo in the same shooting session, without a thorough chamber scrubbing, is a recipe for getting a stuck case. You can get away with it with true 5.56 chambers, but not so much in 223 chambers, but it can still happen. Definitely don't do that in a class. It will be an exercise in frustration when stuck cases suddenly repeat over and over again.
fivefivesix
11-08-10, 22:01
that was one of the reasons i did it. it ran the wolf flwless. so i said lets mix it up. its the new polymer coated stuff and my dd barell is stamped 5.56. but it ran great
Doc Safari
11-09-10, 09:02
I'm seriously investigating the mid-length system, but the carbine AR is a known quantity with years of service and the mid-length is not. Logically, it sounds like the mid-length would be more durable and reliable, but then again maybe not. It's still not a full length gas system. Maybe the mid-length rifle's bolt lasts 3,000 rounds longer than a carbine's bolt? Maybe it's a negligible difference? Until I see some actual data I say it's a matter of preference also.
Run your carbine with a LMT enhanced bolt, H buffer and M16 carrier, change cam pin from time to time and your carbine will outlast a middy with a standard bolt, car buffer and semi carrier by a lot. Parts play a larger role in durability. I guess a middy with good parts would out last it but the barrel would be shot out before this happens.
IMO gas port erosion is the big killer for ARs in general.
That's a good point. Are there any middies in the Military? Are any units deploying any middies?
A few IPs/SMEs on TOS confirmed they were in use on some Recon / accurized M4 variants, though all were custom-built/tailored to those using them. None were standard issue equipment. The standard Recce gas system is carbine-gas length.
I don't understand why when making barrels really short manufacturers don't go ahead and modify the dwell time on the carrier. For the same effect of carbine vs mid gas sytem and the impulse delay, you can add this to to the cut in the carrier in the "dwell" time to get the same effect. You have to be careful because soon the extractor pin that is held in by the bolt group begins to stick out when the bolt is forward but then you just have to step this to keep it in while the bolt is sticking out of the carrier. That is if you go that far, just add enough dwell time to keep it retained and see what that gets you. :big_boss:
ForTehNguyen
11-11-10, 15:25
I'm seriously investigating the mid-length system, but the carbine AR is a known quantity with years of service and the mid-length is not. Logically, it sounds like the mid-length would be more durable and reliable, but then again maybe not. It's still not a full length gas system. Maybe the mid-length rifle's bolt lasts 3,000 rounds longer than a carbine's bolt? Maybe it's a negligible difference? Until I see some actual data I say it's a matter of preference also.
even ignoring all of these, the extra 2" of handguard is a lot more comfortable than extending the stock 2" to make up for it on a carbine. You can hold a midlength more compact that way. Ergonomic advantage alone is worth it.
I don't understand why when making barrels really short manufacturers don't go ahead and modify the dwell time on the carrier. For the same effect of carbine vs mid gas sytem and the impulse delay, you can add this to to the cut in the carrier in the "dwell" time to get the same effect. You have to be careful because soon the extractor pin that is held in by the bolt group begins to stick out when the bolt is forward but then you just have to step this to keep it in while the bolt is sticking out of the carrier. That is if you go that far, just add enough dwell time to keep it retained and see what that gets you. :big_boss:
what you're promoting would require the action to be longer, thus, creating a proprietary rifle that would be longer than the ar15 and have proprietary internals. That's unacceptable.
It's easier to move the gas port closer to the muzzle.
no, people are doing it now, just not advertising it,
this is done on the shrike AR style system, it doesn't change much of anything in the end. you can see it more upclose under the industry section in ARfcom.
On that system notice the stepped pin, that is because of the huge dwell addition. You can split the difference and not have to do that.
Not a different system at all, just a small tweak
**Did you know(this could be wrong) that in the beginning(stoner days), they didn't put a dwell in carrier, immediately noticed an issue and a dwell was added, it certainly wasn't tweaked when they shitcanned it to make the M4.
I have a few questions.
The fellow over at 03designgroup has mentioned he has cut his carbine gas system rifles down to 14.5 and his middys at 16 so they have the same length of barrel forward of the gas port. Is this the key to the middy vs. carbine debate?
Also vuurwapen blog mentioned how Colt's 16 carbine gas system guns had bigger gas holes in the barrels than their 14.5 counterparts. Is this something we need to account for, gas hole size?
I remember Ken Elmore before he left Colt in my AR-15 armorer's course discussing the gas system at the end of class. He wrote up on the board some thing like this:
__________A_____________/\_______B___
A being the part of the barrel before the gas hole.
/\ being the gas hole.
B being the part of the barrel forward of the gas hole.
Ken said if you change one of those you have to change the others otherwise you are going to have problems. It was part of his warning to us not to cut barrels down without having someone do it who really understood how changing one changed the others. He was really talking about changing B. He pointed out that the Commando, M4, and M16 gas ports went big, small, and big. Commando was big because it needed gas now, M4 small because it had time with a longer B, and M16 big again because it needed more gas for the long A.
The question I have besides the one above is how does changing A 2 inches forward in a 16 inch gun affect /\. Does /\ need to be bigger or smaller? What about taking a 16 carbine and cutting 1.5 inches off of B?
Heavy Metal
11-11-10, 21:31
what you're promoting would require the action to be longer, thus, creating a proprietary rifle that would be longer than the ar15 and have proprietary internals. That's unacceptable.
It's easier to move the gas port closer to the muzzle.
No he isn't.
He is talking about using the cam path on the LMT Enhanced carrier on a carrier with standard gas venting.
Such a carrier would be useable in any length configuration and only make them all run better IMO.
I have a POS Bushmaster 14.5" carbean upper with like 30k rounds through it. It still head spaces ok, and will hold under 2" groups at 100 as of last weekend.
If you're shooting only 1000 per year... you'll get at least 30 years useage out of it.... give or take. :p
Is everything original on the gun? That is impressive.
I have a few questions.
The fellow over at 03designgroup has mentioned he has cut his carbine gas system rifles down to 14.5 and his middys at 16 so they have the same length of barrel forward of the gas port. Is this the key to the middy vs. carbine debate?
Also vuurwapen blog mentioned how Colt's 16 carbine gas system guns had bigger gas holes in the barrels than their 14.5 counterparts. Is this something we need to account for, gas hole size?
I remember Ken Elmore before he left Colt in my AR-15 armorer's course discussing the gas system at the end of class. He wrote up on the board some thing like this:
__________A_____________/\_______B___
A being the part of the barrel before the gas hole.
/\ being the gas hole.
B being the part of the barrel forward of the gas hole.
Ken said if you change one of those you have to change the others otherwise you are going to have problems. It was part of his warning to us not to cut barrels down without having someone do it who really understood how changing one changed the others. He was really talking about changing B. He pointed out that the Commando, M4, and M16 gas ports went big, small, and big. Commando was big because it needed gas now, M4 small because it had time with a longer B, and M16 big again because it needed more gas for the long A.
The question I have besides the one above is how does changing A 2 inches forward in a 16 inch gun affect /\. Does /\ need to be bigger or smaller? What about taking a 16 carbine and cutting 1.5 inches off of B?
it's not about set lengths, its about ratio. the gas port should be about 5/8ths of the way down the barrel from the bolt face.. .625% gas to .375 dwell, or something close to that.
gas port size is more complicated.. but as you said, short dwell- larger port.. over-dwelled, shorter port.. longer system, larger port.
unless you're sabre.. then you just use .080 for everything.
This thread is a big relief to me. I just purchased a ddm4 carbine about 2 months ago. I was sure that I had bought the best carbine in my price range until I started seeing the craze for midlength systems. I found thinking that I may have made the wrong decision and maybe should have bought a midlength carbine. I am new to the rifles and am trying not to get too caught up in the newest coolest shit craze. I almost bought a new lower to build a midlenght m4 recently but now I think that the money would be better spent on ammo and learning to shoot the carbine length system I have. I will probably shoot no more than 5k next year and I am sure the ddm4 will serve me well.
Best statement in this thread.
No he isn't.
He is talking about using the cam path on the LMT Enhanced carrier on a carrier with standard gas venting.
Such a carrier would be useable in any length configuration and only make them all run better IMO.
This is correct, I was unaware that it was public knowledge for LMT with their carrier. More Dwell is in no way harmful, at all. It makes up for many situations gone bad because of unlock timing and pressures. I wish this was pushed more as a solution that should be implemented on all AR brands, it is only a change in the 4-AXIS CNC program cutting the slot, the gas port location is still very critical but this would really really help extraction and hence reliability.
This is correct, I was unaware that it was public knowledge for LMT with their carrier. More Dwell is in no way harmful, at all. It makes up for many situations gone bad because of unlock timing and pressures. I wish this was pushed more as a solution that should be implemented on all AR brands, it is only a change in the 4-AXIS CNC program cutting the slot, the gas port location is still very critical but this would really really help extraction and hence reliability.
Smart guys here:)
The philosophy I subscribe to is run the longest gas system you can in DI.
If that's Midlength because you have a 14.5''+ barrel, if that's a Rifle Length at 18''+, Carbine length at 14.5''or less. (And honestly, alot of people are having great results with running Mid-Length gas systems on 14.5'' so I might just run a carbine length on barrel lengths shorter than 14.5'')
I mean, faster gas port erosion, faster parts wear at higher pressures and more are the concerns.
But again, I haven't seen those documented. They would seem to be true, but I haven't seen it tested either.
What you do know is that it gives more dwell time and less recoil for 2'' of gas tube, a longer handguard, (which IMHO is better for handling the weapon, and even if you don't handle way out there, it's nice to have options, you can attach a bipod, etc.), and usually has a lot less extractor issues as it isn't as "violent" extraction.
Use what you want, but I don't see a downside with going with the longest gas system available as a general rule of thumb.
constructor
11-13-10, 02:46
The only 5.56 bolts I have broken were in carbine gas rifles, one was a Y/M chrome bolt that may have only lasted 1000 rounds the others lasted 4-5000 and they all broke at the cam pin hole. The DOD contractor produced bolts last much longer than the commercial grade bolts. After checking the hardness I do not believe the commercial bolts were Carpenter alloy #158(P6) or were hardened to mil spec. the bolts tested in the low 50s.
Off on a small tangent it appears most chrome carriers are deco chrome(like a car bumper) not hard chrome like the bore inside of a mil spec carrier.
Bingo:
The middies are nice and shoot a bit smoother.... but not worth dumping a perfectly good carbean over. You just build another gun and go from there.
And there are a lot of variables from brand to brand. According to Walt Krulek ( IIRC ) , Armalite pioneered the midlength to save money on warranty work.
I have seen pictures of the comparative wear on parts from a 20 inch standard rifle , a 16 inch middy , and a 14.5 (?) carbine. The pic's impressed me. I couldn't find a link now to save my life -- and who knows if it was honest test or barfcom recycled BS?
Belmont31R
11-14-10, 03:34
Careful with that combo. Mixing steel and brass ammo in the same shooting session, without a thorough chamber scrubbing, is a recipe for getting a stuck case. You can get away with it with true 5.56 chambers, but not so much in 223 chambers, but it can still happen. Definitely don't do that in a class. It will be an exercise in frustration when stuck cases suddenly repeat over and over again.
I mix brass and steel case all the time, and never had a single issue.
RogerinTPA
11-14-10, 09:28
I mix brass and steel case all the time, and never had a single issue.
I used to have the same opinion, right up to when it happened to me a few times using a 6920 and an LMT.
Doc Safari
11-15-10, 09:23
The only 5.56 bolts I have broken were in carbine gas rifles, one was a Y/M chrome bolt that may have only lasted 1000 rounds the others lasted 4-5000 and they all broke at the cam pin hole. The DOD contractor produced bolts last much longer than the commercial grade bolts. After checking the hardness I do not believe the commercial bolts were Carpenter alloy #158(P6) or were hardened to mil spec. the bolts tested in the low 50s.
This is what I'm wondering: is premature bolt breakage inherent to carbine length rifles, or just substandard bolts, or both?
1776 Patriot
11-15-10, 09:41
It all comes down to personal 'preference' IMO. Really, this isn't really an issue for me although this issue of carbine vs Mid seems to be more of a concern as of late.
It really seams like mid lengths are becoming very fashionable these days, I've notice more and more people selling off their carbine/M4 uppers lately on other forums and more folks berating carbine length systems. As for me I have no preference. I just want at least one of each gas system.:p
It really seams like mid lengths are becoming very fashionable these days, I've notice more and more people selling off their carbine/M4 uppers lately on other forums and more folks berating carbine length systems. As for me I have no preference. I just want at least one of each gas system.:p
That's the thing I'm wondering about. It's fashionable and it's currently the "in thing." Will we look back 5 years from now when everyone has gone on to the new "in thing" and wonder what we were thinking??? :laugh:
Jay Cunningham
11-16-10, 11:23
So who here thinks they will suddenly shoot better if they switch from a carbine length system to a mid length system?
Who here thinks that they will easily wear out their carbine but not their middy?
D. Christopher
11-16-10, 13:42
The difference in wear between a mid-length and a carbine made by the same manufacturer or at least made to the same standards is so small as to be insignificant or inconsequential. Mid-lengths fit me better and are easier to shoot accurately, especially on follow up shots but I never bought into the claims regarding wear and never factored that into my buying decisions. Buy what fits you best and then shoot it as much as you can or as little as you want. You replace a few gas rings, some springs, a few bolts, a carrier, and then eventually a barrel. If you stick with the proven names it will take quite a while to get there.
Who here thinks that they will easily wear out their carbine but not their middy?
A mid length decreases dwell time. That CAN'T be a bad thing.
It negates the use of a non standard heavier buffer, it may negate the need for extractor improvements, all in an effort to have reliable extraction/ejection.
Jay Cunningham
11-16-10, 14:50
A mid length decreases dwell time. That CAN'T be a bad thing.
It negates the use of a non standard heavier buffer, it may negate the need for extractor improvements, all in an effort to have reliable extraction/ejection.
Never mentioned "a bad thing." How will the middy improve your shooting ability? How much sooner will the car wear out and break?
ForTehNguyen
11-16-10, 14:57
i can see it improving shooting ability just from a pure ergonomics standpoint, 2" longer handguard = stock retracted 2", better balance
Jay Cunningham
11-16-10, 15:03
i can see it improving shooting ability just from a pure ergonomics standpoint, 2" longer handguard = stock retracted 2", better balance
So you think that someone who doesn't shoot a car length gas system very well can be handed a mid length and they will then shoot better?
Never mentioned "a bad thing." How will the middy improve your shooting ability? How much sooner will the car wear out and break?
nobody knows, as you know.. it's all speculation. but it stands to reason.
the middy "craze" or whatever you want to call it is due mostly to over simplified statements on the internet that people take as gospel. somebody wrote something like "it stands to reason that a less violent, smoother shooting gun will perhaps tend to extend bolt life," which was then taken by somebody else and simplified to read "middies will probably last longer than carbines," carried on down the line, everyone is convinced that carbine systems are worthless and mid-length guns are revolutionary solutions to the carbine "problem."
or something like that.
there's no "data" out there.. nobody knows if or how much. but now that middies are at least established as reliable- would you buy a carbine if a mid met your needs?
Jay Cunningham
11-16-10, 15:06
nobody knows, as you know.. it's all speculation. but it stands to reason.
the middy "craze" or whatever you want to call it is due mostly to over simplified statements on the internet that people take as gospel. somebody wrote something like "it stands to reason that a less violent, smoother shooting gun will perhaps tend to extend bolt life," which was then taken by somebody else and simplified to read "middies will probably last longer than carbines," carried on down the line, everyone is convinced that carbine systems are worthless and mid-length guns are revolutionary solutions to the carbine "problem."
or something like that.
there's no "data" out there.. nobody knows if or how much.
Now that's pretty close to the mark far as I can tell.
but now that middies are at least established as reliable- would you buy a carbine if a mid met your needs?
I just did as a matter of fact.
How will the middy improve your shooting ability? How much sooner will the car wear out and break?
I've never made an argument about any improved shooting ability so I'll stay away from that topic.
Now let's talk about wear and tear. As far as I'm concerned, the only parts of the rifle to examine is the bolt.
The carbine system wants to unlock it earlier and with much greater torquing force. It stresses the locking lugs and the area surrounding the cam pin hole as the pin impacts the end of the cam track due to abnormally high carrier speed.
How much effect does the carbine system have over the mid length system in terms of bolt wear/breakage? I simply don't know....
....but I'll stick to mid lengths for peace of mind.
Simply personal preference. I prefer a middy due to the multitude of examples stated previously.
Longer sight radius for us iron guys, more mild recoil, and smoother mechanical operation. Pretty significant difference at the range...not so sure in combat that it would amount to that much.
As far as wear...I doubt much difference would be noted. The bolt is slammed back into a buffer/spring and returned with additional force in the carbine. How much more and how that relates to wear is about the same arguement between an investment cast and forged M14 receiver. I doubt anyone would ever shoot enough rounds to find the differences. They may be accentuated in extreme cold environments though.
I don't know if the gas system length makes me a better shooter, but I strongly believe that having the extra rail length has enabled me to operate the weapon more efficiently. For the last year I've been messing with rifles that have mid-length rail systems (KAC SR15, LWRC M6A2, DD M4). I recently put a MOE forearm on my 6520, along with a light and did some drills with it. I find the carbine rail system cramped and does not seem to give me the control that a longer rail does (I don't have a timer, so I can't prove it). But that's independent of gas system length. The DDM4 is one of the slickest packages around IMO, and it has the carbine length system.
For me and my uses, I like the longer rails. The benefits of the softer recoil, reduced dwell time, etc. of the mid-length are academic for the most part; more theory and conjecture than reality. But longer rails have proven a benefit to me, unrelated to the length of the gas system.
So who here thinks they will suddenly shoot better if they switch from a carbine length system to a mid length system?
Who here thinks that they will easily wear out their carbine but not their middy?
i can tell you i started shooting better when i went from my carbine to my full size colt. Not sure if its the upper or sights but do like the feel of my full size rifle as apposed to my carbine. i'm seriously thinking of selling off the 15 1/2" barrel and going with a middy not because its the in thing but because i think i will like the sight radius better
vicious_cb
11-16-10, 17:21
I can't believe people are using longer sight radius on the middy in this day and age enough to warrant a switch from a shorter gas system.
I can't believe people are using longer sight radius on the middy in this day and age enough to warrant a switch from a shorter gas system.
some people still shoot irons. my mid 14.5 has irons. have you seen the dissipater thread?
Now that's pretty close to the mark far as I can tell.
I just did as a matter of fact.
well make a case- why? do you feel the mids are lacking something?
i was skeptical when 14.5 mids started coming out. i've always been a believer that more gas is better than less gas. but the mids seem to work, and people claim they're softer shooting.
my mid 14.5 doesn't shoot any better than anything else i own.. it also doesn't shoot any worse. so far, i'm unimpressed- but since i DO get a longer sight radius, and, in theory, it should help in longevity, i remain on the slightly positive side of neutral. if a mid meets all my needs, and a carbine doesn't meet them better, then i'll go with a mid.
ETA- on the same note... if a carbine gives me any advantage, even if just a small one, over a similarly configured mid, then i'd probably go with a carbine- think weight.
My only interest in mid lengths is that with a correct 5.56mm chamber, theoretically the mid length system will extract/eject 223 brass saami, 223 steel saami, and 5.56mm nato brass better than with the carbine system with less chance of a torn rim/case head or stuck casing.
Between the two gas lengths, I don't think any other perceived improvements matter except better cycling of the rifle using various types of 223 and 5.56mm nato ammunition.
Jay Cunningham
11-16-10, 18:38
well make a case- why? do you feel the mids are lacking something?
I don't need to make the case for the carbine gas system - the mountains of data from real world use of 10.3, 11.5, 14.5 and 16 inch carbine length guns already makes the case rather eloquently.
What I *am* pointing out is the irresponsible hype suggesting that if you are not "running" a mid length "platform" you are somehow at some kind of disadvantage. I was always taught that it's the singer, not the song; but here we have thread after thread where the magic mid length will supposedly make you uber lethal.
When drum-banging proponents of the middy are pressed, all they have is theoretical "I feel" stuff to back up their claims.
Show me the hard data on how the guns perform in the real world, then we'll talk.
Jay Cunningham
11-16-10, 18:39
theoretically
Pretty much this.
CaptainDooley
11-16-10, 19:29
Jay, as usual, states his opinion with no sugar-coating - which I happen to love.
I personally bought a LW middy for my latest gun, just to try something new - I had a BCM 16" carbine length and a 6920, so I figured it was time for something different. I never felt under gunned with my other two carbines, and I don't feel any more deadly with the middy (though I do enjoy using the LW for an all day class way more than the other two).
I realized how bad the "if it's not middy it's crap" thinking was getting when people criticized LAV's new DD rifle for not being a middy - as if all the thought, theory, and experience that went into the design and accessories was completely worthless because LAV made a mistake and used the wrong gas system.
Sure, I'd buy more middys if they met my needs, but I'm not about to discount the viability of the standard carbine gas length.
I figure that since I'm going to be running a 9-12" rail to hang my stuff off of and get my support hand out where it helps me control the weapon, it may as well have a longer gas tube.
Magic_Salad0892
11-21-10, 04:29
I can see it being a value on suppressed guns, or guns running heavy buffer with strong spring setups. (IE: Mine.)
It helps with recoil and dwell time, with longer sight radius, and a longer rail.
Those are the main arguments: Or at least - the valuable ones.
The wear and tear arguments are almost moot point, because if you practice preventative maintenance than you'll have replaced the ''problem'' parts before they break.
For me however, I think that midlengths are better than carbines. Running as long a gas system as you can while maintaining reliability has always made sense to me.
Especially when you start running heavy buffers to reduce bolt bounce, and stuff for suppressed guns.
Tuning gas ports should help out even more. I just wish there was a ''standard'' gas port dimension for mid-lengths.
I just did as a matter of fact.
IIRC that was the Vickers DD gun, right? Wasn't that purchase about a whole lot of other stuff besides the length of the gas tube? If the whole rest of the gun had been identical but had a mid-length gas tube would you still have bought it or would you have passed?
I agree with your posts in this thread, BTW. Of late there have been a whole lot of Monday morning engineers trying to wring all sorts of theoretical advantages out of guns they don't shoot enough to actually notice the difference downrange or on the timer. I have also heard shooter muttering behind me at the range that "of course he shoots like that, he has a mid-length gas system and a muzzle brake". :rolleyes: I have a new policy wherein I'm going to start taking their gun and spank their ass with it. They can shoot mine if they want to.
Jay Cunningham
11-21-10, 06:00
IIRC that was the Vickers DD gun, right? Wasn't that purchase about a whole lot of other stuff besides the length of the gas tube? If the whole rest of the gun had been identical but had a mid-length gas tube would you still have bought it or would you have passed?
Yep, it certainly was, and you're right it was about the whole layout of the gun. If it had been a mid-length I still would have bought it because the gas system argument is overblown and I'm comfortable "running" either. FWIW, this gun is a one-for-one replacement for my previous "go to" gun which was an LE6920 configured in largely the same fashion. Carbine gas system! :blink:
I agree with your posts in this thread, BTW. Of late there have been a whole lot of Monday morning engineers trying to wring all sorts of theoretical advantages out of guns they don't shoot enough to actually notice the difference downrange or on the timer. I have also heard shooter muttering behind me at the range that "of course he shoots like that, he has a mid-length gas system and a muzzle brake". :rolleyes: I have a new policy wherein I'm going to start taking their gun and spank their ass with it. They can shoot mine if they want to.
Yep, it's the singer, not the song. Now that doesn't mean that there aren't guns that are easier to shoot than other guns. If you have a gun with shitty sights and a very heavy trigger and a poorly designed grip, it's obviously going to be harder to shoot well. But all things being equal, if you have an AR-15 with a car gas system and an AR-15 with a mid-length gas system, you are going to shoot them both about the same.
And if you suck the middy isn't going to help you much - only training and range time will.
Unless we do a wholesale switch back to rifle gas systems - they shoot really smooth!! And have a super long sight radius!! :laugh:
Yep, it certainly was, and you're right it was about the whole layout of the gun. If it had been a mid-length I still would have bought it because the gas system argument is overblown and I'm comfortable "running" either. FWIW, this gun is a one-for-one replacement for my previous "go to" gun which was an LE6920 configured in largely the same fashion. Carbine gas system! :blink:
Yep, it's the singer, not the song. Now that doesn't mean that there aren't guns that are easier to shoot than other guns. If you have a gun with shitty sights and a very heavy trigger and a poorly designed grip, it's obviously going to be harder to shoot well. But all things being equal, if you have an AR-15 with a car gas system and an AR-15 with a mid-length gas system, you are going to shoot them both about the same.
And if you suck the middy isn't going to help you much - only training and range time will.
Unless we do a wholesale switch back to rifle gas systems - they shoot really smooth!! And have a super long sight radius!! :laugh:
I'm glad we can find *something* we can agree on. :sarcastic:
Th3Revreant
11-21-10, 16:00
IMHO, its really a matter of preference for the user and as Nutnfancy on youtube states, POU(philosophy of use) is for the particular rifle you are using. Me being a bigger dood, I like the mid length due to its longer grip and if installing a quad-rail of some sort, it gives you a little more real estate to play around with. A down side to it is, in my own experience, parts are a little harder to come by that fit my middy. Either or, more personal preference than anything for a standard civilian user.
LowSpeed_HighDrag
11-21-10, 17:02
IMHO, its really a matter of preference for the user and as Nutnfancy on youtube states, POU(philosophy of use) is for the particular rifle you are using. Me being a bigger dood, I like the mid length due to its longer grip and if installing a quad-rail of some sort, it gives you a little more real estate to play around with. A down side to it is, in my own experience, parts are a little harder to come by that fit my middy. Either or, more personal preference than anything for a standard civilian user.
OMG, please dont quote NutnIntelligent.
In this day and age youre having a hard time finding middy parts? Like what?
Th3Revreant
11-21-10, 18:31
just looking for OD green standard middy handguards and OD green 6pos stock. Sorry for the hijack. I only need the standard hg because of the small rail sections im using. Having issues locating a decent, used free float quad-rail for it.
Pretty much this
I should have said factually.
Increasing the gas system length, assuming the barrel length and gas port diameter remains the same, will decrease dwell time and affect the extraction process.
How much better is the mid length system over the carbine length system? We don't know......
The philosophy I subscribe to is run the longest gas system you can in DI.
If that's Midlength because you have a 14.5''+ barrel, if that's a Rifle Length at 18''+, Carbine length at 14.5''or less. (And honestly, alot of people are having great results with running Mid-Length gas systems on 14.5'' so I might just run a carbine length on barrel lengths shorter than 14.5'')
I mean, faster gas port erosion, faster parts wear at higher pressures and more are the concerns.
But again, I haven't seen those documented. They would seem to be true, but I haven't seen it tested either.
What you do know is that it gives more dwell time and less recoil for 2'' of gas tube, a longer handguard, (which IMHO is better for handling the weapon, and even if you don't handle way out there, it's nice to have options, you can attach a bipod, etc.), and usually has a lot less extractor issues as it isn't as "violent" extraction.
Use what you want, but I don't see a downside with going with the longest gas system available as a general rule of thumb.
great post.
i went this route with my 16'' carbean/bushy.
cutt the barrel back to 13.5 added a levang comp.
m16 carrier and H2 buffer.
works great.
no issues at all, softer shooting.
peabody
I don't have the link, but I thought there was a statistically higher rate of bolt breakage in M4s vs M16.
It's a fact that port & chambers pressures are lower as you move down the barrel.
Here's a good pic (http://ar15barrels.com/gfx/223plot.gif) illustrating the point.
http://ar15barrels.com/gfx/223plot.gif
do carbines show any pattern of more parts replacement, or parts failure than a mid length? what parts fail on carbine's that would have lasted longer in a mid length for a given round count? I'm just looking for examples of mid lengths lasting longer vs carbines.
I personally picked a BCM 14.5 inch LW carbine over a 16 inch LW mid length when i recently made my last purchase. So far I love this gun, very compact, very light, very reliable, and it flat out shoots great.
do carbines show any pattern of more parts replacement, or parts failure than a mid length? what parts fail on carbine's that would have lasted longer in a mid length for a given round count? I'm just looking for examples of mid lengths lasting longer vs carbines.
there's none
It's a fact that port & chambers pressures are lower as you move down the barrel.
I wouldn't dispute this, but how significant of a difference is it?
If low pressure was ideal, we would all use rifle gas systems.
Magic_Salad0892
11-23-10, 02:20
I wouldn't dispute this, but how significant of a difference is it?
If low pressure was ideal, we would all use rifle gas systems.
Dwell time issues on 14.5'' and 16.1''.
If people could do it reliably I bet we'd see rifle gas 14.5'' guns tomorrow.
Everything is a balancing act.
For best extraction, you want to have the chamber pressure as low as possible. This implies a long gas port location.
In order to cycle the action, you need a particular amount of gas impulse. This is pressure x time. Time that the piston is under pressure is related to the distance from the gas port to the muzzle. More time implies a short gas port location or a long barrel.
Pressure in the gas system is related to the available chamber pressure and the gas port size.
The rifle length system extracts well under low chamber pressures, but requires a 20" barrel.
The carbine system suffers from early extraction and high gas port pressures but works well with barrels as short as 10"-12".
The midlength system splits the difference and works well with 14-16" barrels.
Is a carbine system going to be more reliable with cheap low powered .223 that might short stroke a middy? Serious question.
these carbine vs mid threads are always an example of how poor the ar15 system is mechanically.
There's only 3 things we can manipulate on a 223/5.56mm ar15 for best performance.
1. gas port location
2. extractor tension.
3. 5.56mm NATO chamber.
Some things we can't change in the 223/5.56mm ar15 system is....
1. extractor circumference
2. weak rim on 223/5.56mm casing
3. poor taper on 223/5.56mm casing
4. lack of primary extraction on ar15 system
Jay Cunningham
11-24-10, 23:01
these carbine vs mid threads are always an example of how poor the ar15 system is mechanically
I just don't see it.
these carbine vs mid threads are always an example of how poor the ar15 system is mechanically.
There's only 3 things we can manipulate on a 223/5.56mm ar15 for best performance.
1. gas port location
2. extractor tension.
3. 5.56mm NATO chamber.
Some things we can't change in the 223/5.56mm ar15 system is....
1. extractor circumference
2. weak rim on 223/5.56mm casing
3. poor taper on 223/5.56mm casing
4. lack of primary extraction on ar15 system
=============================
What about also "manipulating" :
1. gas port size
2. buffer weight
3. ??
.
What about also "manipulating" :
1. gas port size
2. buffer weight
Yes the port size and buffer weight can definitely be changed for a desired result.
The reason I didn't mention gas port size is because of the possibility of erosion indifference. Meaning, although an M4 barrel can be manufactured with a smaller gas port diameter, it will only delay the erosion process and will eventually end up as worn out as a regular M4 barrel gas port but with more rounds through.
I have no way of proving this and that's why I left it out. But the idea is that the size of the port will not decrease the violent abrasion/pressure of hot gas closer to the chamber as opposed to a gas port drilled closer to the muzzle of the same barrel length.
I left out buffer weight because I figured increasing the gas system length would be a better permanent solution. This would be purely opinion at this point.
Tactical Joke
11-25-10, 00:37
I've only owned middies until recently. Honestly, when I picked up my first one, I simply preferred the look of the middies on a 16" barrel.
Now that I have a carbine length, I prefer the increased real estate and longer site radius of the mids.
If I had started with carbines, I don't think I'd spend the cash to replace them with mid-lengths unless someone could show me a controlled study showing significant reliability improvements, but I don't expect to buy carbine length gas unless I'm getting a shorty.
mkmckinley
11-25-10, 00:43
=============================
What about also "manipulating" :
1. gas port size
2. buffer weight
3. ??
.
4. Dwell time (for example LMT enhanced carrier)
5. Buffer spring rate
6. Buffer tube length
7. Carrier gas venting
8. Gas tube length and volume
9. BCG weight
10. Bullet weight and powder charge
11. Muzzle device/ suppressor
4. Dwell time (for example LMT enhanced carrier)
I would love hard evidence that proves a tiny bit of more space on the camming track is going to significantly increase extraction reliability for high pressure 5.56mm nato ammo, as well as 223 steel cased ammo in various 14.5/16" carbine/mid-length systems, assuming everything else is untouched.
I would love hard evidence that proves a tiny bit of more space on the camming track is going to significantly increase extraction reliability for high pressure 5.56mm nato ammo, as well as 223 steel cased ammo in various 14.5/16" carbine/mid-length systems, assuming everything else is untouched.
The extra cam track length buys you more time for chamber pressure to drop.
This time can also be had by going to a longer, rifle length gas for example.
If you compare the extra time delay by each, and they are similar, you could conclude they both extract under similar chamber pressures.
Not "hard evidence", but something to think on.
On a related note, all the other systems have gobs of cam travel, on the order of .75". These are also usually in conjunction with fast acting, high impulse piston systems, so the cam track is the only way to achieve the delay.
On the DI system, I believe there is a gas delay effect that partially makes up the opening delay, with the small cam track delay making up the rest. This works best on rifle length gas systems.
Going to shorter gas systems eats into the delay provided by the gas system.
I think a carbine gas would be fine IF the cam track could be lengthened to compensate.
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