View Full Version : M855A1 with H6 buffer?
To those in the know,
I was able to scrounge up an H6 buffer and a new action spring from a CMRE yard.
My rifle is currently running a standard H buffer, and my brass is ejecting between the 1-2 o clock. I've replaced the extractor and spring with the BCM upgrade kit, and I want to know if there are any members here running H3s with 14.5" carbine gas setups. The A1 is a ridiculously hot load, and I'm thinking that since the H6 weighs the same as the H3 just with six weights instead of three, it might work.
I won't be able to get an H2, that's already out of the question. Any idea how well the H3s work in carbines?
With the 3 steel weights inside a carbine buffer, and the 3 tungsten weights inside a H3, the roll pins can be driven out and you can make any combination of weights to make your own buffers, giving you the option of having carbine, h1, h2, and h3.
What is an H6? Carbine sized buffer? If so... yes, I'd think that would help with that goofy ammo.
Damn.. I was just reading a write up on that a1 ammo. Absolute worst thing they could have done.... come up with a load HOTTER for the m4??? Just dumb.
The H6 is a CAR length buffer with 6 tungsten "half weights" inside.
It is probably as good or better than a regular H3.
With extra hot M855A1, it's likely to work very well together.
As was mentioned, if the H6 happens to be too heavy, you should be able to swap a pair of half weights for a steel weight and make an H4/2.
BufordTJustice
05-25-14, 17:31
To those in the know,
I was able to scrounge up an H6 buffer and a new action spring from a CMRE yard.
My rifle is currently running a standard H buffer, and my brass is ejecting between the 1-2 o clock. I've replaced the extractor and spring with the BCM upgrade kit, and I want to know if there are any members here running H3s with 14.5" carbine gas setups. The A1 is a ridiculously hot load, and I'm thinking that since the H6 weighs the same as the H3 just with six weights instead of three, it might work.
I won't be able to get an H2, that's already out of the question. Any idea how well the H3s work in carbines?
I ran an H3 in my BCM 14.5" middy. You'll be just fine with your carbine using the H6.
Also, what lube are you using?
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The H6 weighs 5.15 ounces -- same as a standard rifle buffer. H3 is 5.40 ounces, H2 is 4.60 ounces.
sinlessorrow
05-25-14, 21:20
To those in the know,
I was able to scrounge up an H6 buffer and a new action spring from a CMRE yard.
My rifle is currently running a standard H buffer, and my brass is ejecting between the 1-2 o clock. I've replaced the extractor and spring with the BCM upgrade kit, and I want to know if there are any members here running H3s with 14.5" carbine gas setups. The A1 is a ridiculously hot load, and I'm thinking that since the H6 weighs the same as the H3 just with six weights instead of three, it might work.
I won't be able to get an H2, that's already out of the question. Any idea how well the H3s work in carbines?
Why did you replace all those things? Were you having extraction or ejection issues or were you just unhappy with where the brass was landing.......Cause that matters little to nothing, you need to just ignore that whole time clock pie chart of ejection. Also why no H2?
Are you current .mil? Where are you getting your A1 stuff if not?
If .mil, maybe try the ammo out in a 20 inch barrel if possible?
SomeOtherGuy
05-25-14, 23:23
Slight veer - H6 buffer is available commercially here:
http://damageindustriesllc.com/product/buffer-carbine-h6
I got one a month or so ago, and was surprised to find that the internal weights don't seem to move at all, unlike the sliding weights on all other carbine buffers I've used. It has the correct weight and is marked as H6.
@GTF425: does your H6 buffer, which I assume is an unquestioned military supply chain item, have weights that move around internally like carbine and H3 buffers, or does it feel like basically a solid piece?
Why did you replace all those things? Were you having extraction or ejection issues or were you just unhappy with where the brass was landing.......Cause that matters little to nothing, you need to just ignore that whole time clock pie chart of ejection. Also why no H2?
I replaced them because I was having chronic FTE issues in January at Ft Polk. Swapped them out less than 1,000 rounds ago.
No H2 because there's no way in hell I'll find one where I am. I was surprised to find any M4 parts at all.
Are you current .mil? Where are you getting your A1 stuff if not?
If .mil, maybe try the ammo out in a 20 inch barrel if possible?
Yes, I'm active and deployed to Afghanistan.
No 20 inch barrel possible. I'm in an Infantry company and we only issue the M4.
@GTF425: does your H6 buffer, which I assume is an unquestioned military supply chain item, have weights that move around internally like carbine and H3 buffers, or does it feel like basically a solid piece?
They slide around, but they don't feel like individual weights like my H does. Kinda like it's one big weight as opposed to the three individual ones.
I'll take the H6 to the range and see how it goes. I was mostly asking just in case anyone in theater had used this combo and had any experience with it. I'm sure it'll work just fine.
Also, what lube are you using?
Synthetic motor oil.
If an H3 runs in a 14.5" middy, I definitely won't have any issues. I appreciate the insight.
Not necessarily convenient for the OP but here's what Damage says about the H6:
This kit contains all the parts necessary to retrofit 20" barrel AR15/M16 rifles with a carbine-type adjustable stock. Allows 20" rifles to be used with heavy body armor and in environments where a more compact weapon is needed. Currently fielded by United States Marine Corps, the H6 buffer allows flawless function of the short carbine recoil action when used on a 20" rifle. Kit contains the following Mil-Spec parts: 5oz H6 buffer, buffer spring, buffer tube (4 position), locking nut and receiver end plate. *
They also have just the buffer for sale.
Damage is having a 30% off sale until June 1. Use code customer30 for discount.
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BufordTJustice
05-26-14, 11:28
Synthetic motor oil.
If an H3 runs in a 14.5" middy, I definitely won't have any issues. I appreciate the insight.
I went far heavier than that, actually. I ran a custom stainless body buffer from Heavybuffers.net that weighed over 8 oz. Worked 100% on. 223 pressure ammo with a Springco blue. Just keep it wet as a virgin hooker and you'll be fine, brother.
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I just want to make sure I am reading this correctly. You are active duty military and you are modifying your service weapon and messing with buffers?
I just want to make sure I am reading this correctly. You are active duty military and you are modifying your service weapon and messing with buffers?
Absolutely. When my rifle is so overgassed it's spitting brass forward, I have no problem swapping a buffer if it'll help with reliability. I know my unit's policy on weapons modifications and this falls well within our regulations.
sinlessorrow
05-26-14, 13:39
Absolutely. When my rifle is so overgassed it's spitting brass forward, I have no problem swapping a buffer if it'll help with reliability. I know my unit's policy on weapons modifications and this falls well within our regulations.
So how can you get a H3, H6 or custom buffer but not a H2? At least the H2 is well proven in the M4A1. Also why did you replace the colt spring which is arguably the best extractor spring.
SomeOtherGuy
05-26-14, 13:44
Just keep it wet as a virgin hooker and you'll be fine, brother.
I thought we had gotten away from the "run it bone dry" mentality? ;-)
So how can you get a H3, H6 or custom buffer but not a H2? At least the H2 is well proven in the M4A1. Also why did you replace the colt spring which is arguably the best extractor spring.
I answered your question in an earlier post: I got the H6 from a CMRE yard. I can not get an H2 or other weight without paying for it because we do not issue them, but the H6s were available to be grabbed with brand new action springs to go with them. *ETA: The reason this buffer has my attention is because of how hot the A1 load is. With green tip, I know the H2 works great and run them in my personal ARs. But A1 is not 855 and the cyclic rate with the H is retarded fast. Hence my curiosity how the 6's work with 14.5 carbines.
I replaced the extractor spring/extractor because we did not have any spares in the arms room. I'm not sure of your military experience, but it's not as easy as saying "I need this" to get stuff. Especially not with the budget cuts we're having. When I have a spare part on hand, I'll use it. Even if it has to come out of pocket. I'm not going to be the guy with a bolt-action M4 bounding across an objective because it takes two months to get parts. Especially when it's as simple as an extractor swap.
The question's been answered, and I'm heading to the range tomorrow to test function. If it's a dud, the H will drop right back in: no harm, no foul. I was asking to see if anyone had any experience with them, and was able to get the answers I was hoping for.
If you'd like to discuss it further, take it to PM.
BufordTJustice
05-26-14, 14:01
I thought we had gotten away from the "run it bone dry" mentality? ;-)
Some have not. Just making sure. ;)
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BufordTJustice
05-26-14, 14:02
Absolutely. When my rifle is so overgassed it's spitting brass forward, I have no problem swapping a buffer if it'll help with reliability. I know my unit's policy on weapons modifications and this falls well within our regulations.
You may also want to have an extractor donut handy. That A1 is stupid hot ammo.
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The question's been answered, and I'm heading to the range tomorrow to test function. If it's a dud, the H will drop right back in: no harm, no foul.
Please let us now how she runs with the H6.
So your life is on the line and you have no problem making a modification and yet you won't pay for something. Yeah, that makes sense.
I answered your question in an earlier post: I got the H6 from a CMRE yard. I can not get an H2 or other weight without paying for it because we do not issue them, but the H6s were available to be grabbed with brand new action springs to go with them. *ETA: The reason this buffer has my attention is because of how hot the A1 load is. With green tip, I know the H2 works great and run them in my personal ARs. But A1 is not 855 and the cyclic rate with the H is retarded fast. Hence my curiosity how the 6's work with 14.5 carbines.
I replaced the extractor spring/extractor because we did not have any spares in the arms room. I'm not sure of your military experience, but it's not as easy as saying "I need this" to get stuff. Especially not with the budget cuts we're having. When I have a spare part on hand, I'll use it. Even if it has to come out of pocket. I'm not going to be the guy with a bolt-action M4 bounding across an objective because it takes two months to get parts. Especially when it's as simple as an extractor swap.
The question's been answered, and I'm heading to the range tomorrow to test function. If it's a dud, the H will drop right back in: no harm, no foul. I was asking to see if anyone had any experience with them, and was able to get the answers I was hoping for.
If you'd like to discuss it further, take it to PM.
So your life is on the line and you have no problem making a modification and yet you won't pay for something. Yeah, that makes sense.
I am wondering if he is saying he wants to try it it before he buys the H2. If it works well he won't have to buy something else?
The point is if my life is on the line I'll buy 10 different buffers if that's what it takes. I have fired M4 carbines with standard springs and H2 buffers and they worked fine. I am pretty sure based on what I have seen (and assuming that ammo is like every is saying) that this carbine will work with an H3. If it doesn't I'll be shocked. Also, he is focused on the idiotic ejection pattern which shouldn't even be a consideration IMO.
I am wondering if he is saying he wants to try it it before he buys the H2. If it works well he won't have to buy something else?
sinlessorrow
05-26-14, 19:05
The point is if my life is on the line I'll buy 10 different buffers if that's what it takes. I have fired M4 carbines with standard springs and H2 buffers and they worked fine. I am pretty sure based on what I have seen (and assuming that ammo is like every is saying) that this carbine will work with an H3. If it doesn't I'll be shocked. Also, he is focused on the idiotic ejection pattern which shouldn't even be a consideration IMO.
BUT THE CHART!!!!!
http://i38.photobucket.com/albums/e106/Captains1911/paper%20punchers/ARejectionpattern.jpg
I am wondering if he is saying he wants to try it it before he buys the H2. If it works well he won't have to buy something else?
This.
For anyone considering running them in carbines with A1, it locks back and cycled 240rds reliably. It's an interim solution if you can get your hands on an H6 in theater.
The point is if my life is on the line I'll buy 10 different buffers if that's what it takes. I have fired M4 carbines with standard springs and H2 buffers and they worked fine. I am pretty sure based on what I have seen (and assuming that ammo is like every is saying) that this carbine will work with an H3. If it doesn't I'll be shocked. Also, he is focused on the idiotic ejection pattern which shouldn't even be a consideration IMO.
The reason I was asking is because we are having some issues with the increased cyclic rate with our M4s, even more so with the Soldiers who have access to cans. We were able to source enough H6s to outfit my Platoon with, and I was asking just in case anyone had hands on experience with this combo in theater already and could share how it worked for them. Seems I'm the first one on M4C to give it a shot, and as you guessed, it works.
To the members who were helpful, I appreciate it.
Given your MIL experience, IG, I figured you'd understand why this would be a question worth asking. Not all of us can afford to pick up 30+ H2/H3s out of pocket, but if what we can find will work, that's better than nothing.
I hear what you are saying. But, you're telling me that a soldier can't afford an H3 buffer for 37.95? I don't have a thousand dollars laying around for H3 buffers either. If it was important enough I would get some money together (or see about unit funds) and I would order them. How long is mail taking now?
When I was there it took about 10 days depending on location.
The reason I was asking is because we are having some issues with the increased cyclic rate with our M4s, even more so with the Soldiers who have access to cans. We were able to source enough H6s to outfit my Platoon with, and I was asking just in case anyone had hands on experience with this combo in theater already and could share how it worked for them. Seems I'm the first one on M4C to give it a shot, and as you guessed, it works.
To the members who were helpful, I appreciate it.
Given your MIL experience, IG, I figured you'd understand why this would be a question worth asking. Not all of us can afford to pick up 30+ H2/H3s out of pocket, but if what we can find will work, that's better than nothing.
I hear what you are saying. But, you're telling me that a soldier can't afford an H3 buffer for 37.95? I don't have a thousand dollars laying around for H3 buffers either. If it was important enough I would get some money together (or see about unit funds) and I would order them. How long is mail taking now?
When I was there it took about 10 days depending on location.
PM sent.
The major issue is a lot of guys don't know why the increased cyclic rate would be a problem, and I absolutely will not force a Soldier to spend money on something he *should* be given. It's his life on the line, and I owe it to him to make sure he has what he needs to fight and kill mother****ers. Anything else is a failure on my part as his NCO.
I get what you are saying, but the chart is not something I would rely on. I know your weapon is overgassed no doubt (because of the shit I have heard about that ammo). But, I would be making this issue well known to the COC so it can be addressed. If you have to piss people off to get through, so be it.
You're right soldiers shouldn't have to spend their money on that, but it's happened before and it will happen again. I would be getting someone to use the unit slush fund that almost everyone has to get them. And I am sure that someone on this end would help facilitate it if necessary.
PM sent.
The major issue is a lot of guys don't know why the increased cyclic rate would be a problem, and I absolutely will not force a Soldier to spend money on something he *should* be given. It's his life on the line, and I owe it to him to make sure he has what he needs to fight and kill mother****ers. Anything else is a failure on my part as his NCO.
The important thing is that the new bullet is lead free. :fie:
BufordTJustice
05-27-14, 08:29
The important thing is that the new bullet is lead free. :fie:
The Earth has been saved!
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while the enviro wackos no doubt were the reason for the change in ammo, the last laugh might be on them, as it may well lead to better recycling and composting of enemy fighters. An article in the current American Rifleman by Major John Plaster (ret) claims the A1 has better accuracy and penetration than the 855. So potentialy more lethal! Too soon to tell, but if his claims are true, could be an improvement, in spite of the political correctness that initiated the program.
Believe the article said best accuracy is achieved w 1/8 twist rather than 1/7.
Wonder if this ammo will be verboten for civilian use since it has a penetrator nose.
Yep. I read that article. The projectile itself seems to be better than ss109, but the monumental stupidity in the rest of the round's constraints and development is disturbing.
BufordTJustice
05-27-14, 10:32
Yep. I read that article. The projectile itself seems to be better than ss109, but the monumental stupidity in the rest of the round's constraints and development is disturbing.
I wonder if std M855 would have faster and more consistent upset if we just cranked chamber pressure and velocity to equal A1?
I bet the differences would be minimal at that point, other than barrier performance.
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I doubt anything will make SS109 a good performer. Regardless... the brain dead powers that be were fixated on a lead free projectile.
If they weren't retarded, and actually had good ammo as their REAL goal, they'd have matched an OTM to the trajectory of the M855.
BufordTJustice
05-27-14, 13:41
I doubt anything will make SS109 a good performer. Regardless... the brain dead powers that be were fixated on a lead free projectile.
If they weren't retarded, and actually had good ammo as their REAL goal, they'd have matched an OTM to the trajectory of the M855.
Agreed. They could have just t used the bonded version of Mk318, which federal had already developed.
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The main reason they went for the "lead free" was the fact the Army got the EPA to fund R&D on the new round.
The round is hot and extremely accurate. In use it is also very lethal.
I found no issues with it not perfectly matching the ballistics of the 855. We are running Aimpoints and ACOGs and anyone with some training knows the BDC in the ACOG is not exact unless you are running M855 at sea-level on a 60 degree day with no wind.
We had H buffers in our M4's and had no issues. With the upcoming M4A1 upgrade we are moving to the H2 so that should solve the any problems that may be out there.
Curious to see the outcome of the H6 in this application.
I would also go as far to say that the Armorer for this unit needs to get out of the MWR, make friends with the 3rd Shop guys, and get parts for these M4's. A leader on the line should not have to be resourcing parts for weapons. There is Guy for that.
There is more wrong with these weapons than the Buffer weight.
The round is hot and extremely accurate. In use it is also very lethal.
What is your definition of "extremely accurate"?
Extremely accurate, to me, means about .5 MOA out of a match grade barrel.
Is it more lethal that M855? M193? Mk262? Mk318? ~62 gr bonded soft point ammo?
It was printing consistent 2-2.5 MOA groups out of issued M4s which is trick with M855. We don't have match barrels so that was impossible to test.
Effects on soft tissue and to the head are very different than M855, M193,and Mk262. I don't have experience with Mk318 to compare it to.
Short range, 50meter and in, hits to head and upper torso are resulting in severe trauma. The copper jacket around the penetrator separates as advertised to create another wound channel or it shatters and creates fragments that dump all the energy into the tissue.
It is also punching through barriers well at less than 150 meters.
Yeah... the bullet sounds like it does some good things. I can see it being a nice round if you're shooting at someone who is in a vehicle.
The increased pressure and stress on the weapon troubles me.
The copper jacket around the penetrator separates as advertised to create another wound channel or it shatters and creates fragments that dump all the energy into the tissue.
That's interesting... if it's fragmenting "as advertised", that treads a very fine line regarding the hague conventions. Specifically, if it was designed and intended to fragment versus incidentally fragmenting.
If we're going to do that, why don't we just cut the crap and switch over to soft point rounds? They retain mass better and are thus actually more humane than fragmenting bullets, but they're obviously designed to do so which makes them a no-no.
I was able to get the answers I needed, and there's no reason to keep the thread open. If you want to discuss the A1 round, go to the terminal ballistics section and contribute to the thread already in place.
If we're going to do that, why don't we just cut the crap and switch over to soft point rounds? They retain mass better and are thus actually more humane than fragmenting bullets, but they're obviously designed to do so which makes them a no-no.
It doesn't matter. The primary goal of the mental midgetry that oversaw this round was LEAD FREE. This projectile seems to work good considering that monumentally idiotic constraint.
How did the H6's work out?
sinlessorrow
05-28-14, 11:59
It doesn't matter. The primary goal of the mental midgetry that oversaw this round was LEAD FREE. This projectile seems to work good considering that monumentally idiotic constraint.
Be hard not to work good. Its a bullet made up of 2 seperate pieces held together by a copper jacket. Doesn't take a ton of velocity to cause the steel tip to break the jacket and seperate the jacket from the copper slug.
Also as far as I remember the lead free was just a way to get funding to get the bullet made by ATK. I could also argue the best bullets out there are lead free *cough* Barnes TSX *cough* and a few other excellent all copper rounds.
I could also argue the best bullets out there are lead free *cough* Barnes TSX *cough* and a few other excellent all copper rounds.
Those are boutique bullets with their own sets of ass aches.... Which reminds me... I wonder if these bullets cause the problems that Barnes bullets cause in some barrels.. with the excessive copper fouling.
I couldn't quite tell if the bullet portion other than the penetrator is all copper. Or a copper core with gilding jacket. The sectioned round looks like one solid piece, but one of the pics said "copper core".
How did the H6's work out?
I was only able to fire 240rds, but I spent somewhere between 30-40 loading either one or two rounds per mag and testing function. The rifle locked back on every empty mag and I didn't have any malfunctions. It cycles smoother and I feel much more confident running them opposed to the H.
GTF, Good to hear. Tool for the tool box.
The biggest worry on this ammo is the steel penetrator is exposed. On feeding it drags the top of the chamber and carves a groove. Redstone has been getting excessive wear from this in testing. Keep in mind that they are running 50,000+ rounds on these things just to see how far it will go. You can imagine what happens once it cuts deep enough with super high chamber pressures.
I didn't see any copper fouling last rotation but it wasn't on my priority list.
IG, with the higher bolt carrier speeds do you think a weak or slow ejector spring would cause the ejection pattern the OP is seeing?
Just a theory based on experience with super dirty carbines.
The biggest worry on this ammo is the steel penetrator is exposed. On feeding it drags the top of the chamber and carves a groove. Redstone has been getting excessive wear from this in testing. Keep in mind that they are running 50,000+ rounds on these things just to see how far it will go. You can imagine what happens once it cuts deep enough with super high chamber pressures.
I didn't see any copper fouling last rotation but it wasn't on my priority list.
I'll keep tabs on both of those this deployment. If my round count keeps up where it is (~3,200 rds in 3 months) then I'm sure I'll see something by the time I RIP out of here.
The biggest worry on this ammo is the steel penetrator is exposed. On feeding it drags the top of the chamber and carves a groove.
Wow. That's interesting. You'd think that this hot load would have trashed the throat before that groove became a huge problem, but who knows?
It probably did, but they ran them until they failed and noticed the grooves.
We will destroy the weapon long before that round count with cleaning and poor maintenance.
We fired 1,000,000 M855 rounds last year training 600 guys and we broke more bolts and trigger springs than anything else.
sinlessorrow
05-28-14, 13:32
Those are boutique bullets with their own sets of ass aches.... Which reminds me... I wonder if these bullets cause the problems that Barnes bullets cause in some barrels.. with the excessive copper fouling.
I couldn't quite tell if the bullet portion other than the penetrator is all copper. Or a copper core with gilding jacket. The sectioned round looks like one solid piece, but one of the pics said "copper core".
I can't remember what the jacket is exactly. I know the slug is solid copper with the steel penetrator on top, but I believe it may be a gliding metal jacket.
We fired 1,000,000 M855 rounds last year training 600 guys and we broke more bolts and trigger springs than anything else.
Trigger spring huh? That's an odd part to break. Doesn't seem like it lives a rough life. The bolts, I get.
I can't remember what the jacket is exactly. I know the slug is solid copper with the steel penetrator on top, but I believe it may be a gliding metal jacket.
Yeah... it's a little confusing. I guess there's a separate core and jacket. Just so close in color it looks to be one piece.
That's a good question about the ejector spring. I am going to try and do a few tests of my own with buffers and stuff. I may even clip an ejector spring down. Sprinco gave me some of their ejector springs and I want to try them also.
GTF, Good to hear. Tool for the tool box.
The biggest worry on this ammo is the steel penetrator is exposed. On feeding it drags the top of the chamber and carves a groove. Redstone has been getting excessive wear from this in testing. Keep in mind that they are running 50,000+ rounds on these things just to see how far it will go. You can imagine what happens once it cuts deep enough with super high chamber pressures.
I didn't see any copper fouling last rotation but it wasn't on my priority list.
IG, with the higher bolt carrier speeds do you think a weak or slow ejector spring would cause the ejection pattern the OP is seeing?
Just a theory based on experience with super dirty carbines.
If you Google M855A1 there are a few good pics of it to included dissected rounds.
Yep. It definitely has it's own separate jacket.
The penetrator will spin inside that jacket on some rounds, so it is just barely hanging on for the trip. Redstone Rep told us that is designed to sheer off on soft tissue. Of course velocity determines the result.
I dont know if they adjusted gas port size on the new M4A1 barrels they are producing but I am sure by now that they have checked gas pressure and dwell times and that drove the H2 portion of the upgrade.
While I am not sure of the H6 move and I am following the why and give a thumbs up on the resourcing and research, this thread has my interest as we will be moving to the M855A1 stateside as soon as our ranges support it.
.... I wonder if these bullets cause the problems that Barnes bullets cause in some barrels.. with the excessive copper fouling...
I assume Hodgdon's new CFE223 powder is what's spec'd for the M855A1. It supposedly dramatically reduces copper fouling.
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I can guarantee you the EPA did not provide funding IRT the EPR development. The only thing the EPA was involved in was setting lead standards that caused the military to move toward lead free munitions
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sinlessorrow
05-28-14, 20:23
I assume Hodgdon's new CFE223 powder is what's spec'd for the M855A1. It supposedly dramatically reduces copper fouling.
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Powder should be SMP-842.
Smuckatelli
05-28-14, 20:54
The biggest worry on this ammo is the steel penetrator is exposed. On feeding it drags the top of the chamber and carves a groove. Redstone has been getting excessive wear from this in testing. Keep in mind that they are running 50,000+ rounds on these things just to see how far it will go. You can imagine what happens once it cuts deep enough with super high chamber pressures.
This is the second time I've heard this in the past month. I attended the Gunner's Combat Marksmanship Symposium at Quantico last month. There was a SFC from Redstone that talked about the groove being the major issue. He claimed they were able to get kabooms at 20-21k rounds. He also said that there is an order about replacing the barrels at 12k rounds to keep on the safe side. He said the reason for 12k and not 19k was that there is no accurate method to get a round count. Every time you bring the weapon to condition 1, even if you don't fire the round, it still causes the groove.
The other issue is that there is only one type of magazine that can be used because on most magazines the tip of the round drags just enough to slow it down a little. If I recall properly it has to do with the parkerized magazines. The tell the difference by the color of the followers...I can't remember which color is good.
From what he said, it is a very accurate round, right up there with match grade ammo.
I was there too. All the way in the back, in the GravelCam Army section. This comes from multiple sources.
If I recall properly it has to do with the parkerized magazines. The tell the difference by the color of the followers...I can't remember which color is good.
Hopefully the brown followers since that is what the Army is buying.
I assume Hodgdon's new CFE223 powder is what's spec'd for the M855A1. It supposedly dramatically reduces copper fouling.
I was mistaken. The projectile looked to be solid copper, but in fact there's a copper core with the same jacket material as M855.
I keep seeing claims that the M855A1 is loaded to higher chamber pressures but cannot find any data to support the claims. The closest thing I've found is the claim that M855 is loaded to 55k and M855A1 is loaded to 63k. Some are claiming that the new round is loaded close to proof round pressures. Proof round pressures are over 70k. The problem with that is NATO specs call for 63k if I recall correctly. It also does not explain what method was used to measure those pressures. Where is the actual data to support the claims?
The article in Rifleman covered that. They bumped the pressure up 3k if I remember right. 62k to 65k or something along those lines.
Dopey Me missed the fact there was two more pages to the American Rifleman article. Still, it does not answer the question as to what method was used to measure pressure. If the NATO method was used, M855 ammo at 53k is well under the NATO spec which, if I recall correctly, is 62k. If M855A1 is 3-5k greater, that's only up to 58k, still less than NATO max. If measured using the SAAMI method, 58k is at the high end but still nowhere near proof load pressures as some claim. The 300 WSM had it's pressure set just over 60k SAAMI when it was introduced.
This sheds a bit different light on over-gassing and the real difference between SAAMI spec 223 ammo and NATO spec 5.56
Still, it does not answer the question as to what method was used to measure pressure.
Regardless of method, It's still an increase of somewhere around 3k on a round that's already rough on the mil M4.
Yes, I realize that. That' why I said it sheds a different light on over-gassing & the differences between 223 & 5.56.
It also begs the question- How does M855 and M855A1 pressures compare to other NATO spec ammo? Is it less? Is it the same? What other NATO spec ammo is considered hard on the rifle? This information raises as many questions as it answers
BufordTJustice
05-29-14, 14:38
Yes, I realize that. That' why I said it sheds a different light on over-gassing & the differences between 223 & 5.56.
It also begs the question- How does M855 and M855A1 pressures compare to other NATO spec ammo? Is it less? Is it the same? What other NATO spec ammo is considered hard on the rifle? This information raises as many questions as it answers
Well here are the mil specs for chamber pressure for M855 on TOS.
http://www.ar15.com/content/page.html?id=434
NATO uses CIP figures to articulate chamber pressure, but the army seems to use a nearly SAAMI equivalent method for their measurements.
I'll bet that to increase muzzle velocity at or above 3100 fps from just above 2950 fps for the M4's 14.5" barrel, a nearly 10% increase in chamber pressure seems to make sense.
We're talking exceeding M193 velocity with a bullet that is nearly as long as a 69 gr SMK/62 gr TSX.
Something has to give. Regardless of the exact figure for A1 chamber pressure, it's wildly excessive. Period.
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W
Regardless of the exact figure for A1 chamber pressure, it's wildly excessive. Period.
When you have to switch from a crimp to 4 aggressive stakes to keep the primers from popping.... that's a CLUE.
I don't care how temp stabile they claim the propellant is. When you're in a hot climate and the gun is over 110 degrees before even firing a shot?? I'd be praying for the gun to hold together, that's for sure.
Smuckatelli
05-29-14, 15:05
I was there too. All the way in the back, in the GravelCam Army section. This comes from multiple sources.
I wish we would have hooked up...at least for a beer afterwards.
I was the civilian that asked if they realized the Navy wouldn't allow them to paint their rifles on ship. I also questioned them on the robot moving targets......that test was rigged.
sinlessorrow
05-29-14, 15:09
Well here are the mil specs for chamber pressure for M855 on TOS.
http://www.ar15.com/content/page.html?id=434
NATO uses CIP figures to articulate chamber pressure, but the army seems to use a nearly SAAMI equivalent method for their measurements.
I'll bet that to increase muzzle velocity at or above 3100 fps from just above 2950 fps for the M4's 14.5" barrel, a nearly 10% increase in chamber pressure seems to make sense.
We're talking exceeding M193 velocity with a bullet that is nearly as long as a 69 gr SMK/62 gr TSX.
Something has to give. Regardless of the exact figure for A1 chamber pressure, it's wildly excessive. Period.
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But it is also not nearly proof loads as some claim.
BufordTJustice
05-29-14, 18:26
Boland says he saw 62Kpsi to 65Kpsi back in 2011.
And 72Kpsi in a 249.
He also says in the same thread that C. Reed Knight was quite alarmed by the pressure signs from the ammo when he evaluated it.
http://www.lightfighter.net/topic/m855a1-specifications-anyone
It seems my statement about it nearly being a proof load remains accurate unless Kevin has since learned additional info.
Take a round that has been chambered a few times with some heat and maybe a little lube. .... KABLOOEY.
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BufordTJustice
05-29-14, 18:34
But it is also not nearly proof loads as some claim.
A proof load is just over 70kpsi and is designed to be fired ONCE. Coming within 6kpsi or 7kpsi of that for EVERY ROUND FIRED THROUGH A GUN is absurd.
The difference between A1 and 855 is almost double the difference between max SAAMI spec .223 and 5.56 NATO.
I highly doubt the army would mince words with regard to chamber pressure that would exaggerate the increase. ... An increase which they refused to PRINT in initial documents.
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GTF425, Thanks for your service! If you got your M4A1's problems all figured out I'm glad. If not and you still need a H2 buffer or whichever buffer for that matter and/or the correct springs, I'd be more then happy to buy them for you. I'd just have to figure out how to get them to Afghanistan. But I'll do it!
Let me know, NYH1.
So a little follow up to this. Though not directly related this is some data I gathered from today. Maybe I missed it, but I was unable to find an exact weight of the H6 buffer.The Colt H3 buffer is listed as approx. 5.4 oz. Today I took a Colt 6920 upper (same gas port .063 as an M4 carbine) and using a standard GI spring and H3 buffer I successfully ran about 30 round of Federal M193 ammunition through the weapon with ZERO issues. Weather was high 80's, using Slip2000 lubricant and a standard full auto carrier and FN military contract bolt with copper spring and black insert.
For those worried about ejection patterns it was pretty consistent at about 300 o'clock. Since I already knew an H2 would work, based on other testing I skipped the BS and went straight to the H3. Obviously with full auto and burst it could be different, but since we know that the M855A1 is hotter something tells me that it is going to work just fine.
I have also built (2) M16A2 configuration uppers and when using the carbine lower receiver extension and a blue Sprinco spring with the H3 buffer and they also cycled with several types of ammunition with ZERO issues.
GTF425, Thanks for your service! If you got your M4A1's problems all figured out I'm glad. If not and you still need a H2 buffer or whichever buffer for that matter and/or the correct springs, I'd be more then happy to buy them for you. I'd just have to figure out how to get them to Afghanistan. But I'll do it!
Let me know, NYH1.
I greatly appreciate the offer, however, we have found a solution with the H6s we could source on our base. I was able to find enough of them to outfit my Platoon with, so we are good to go at this time.
Thank you for the offer.
BufordTJustice
05-30-14, 07:39
So a little follow up to this. Though not directly related this is some data I gathered from today. Maybe I missed it, but I was unable to find an exact weight of the H6 buffer.The Colt H3 buffer is listed as approx. 5.4 oz. Today I took a Colt 6920 upper (same gas port .063 as an M4 carbine) and using a standard GI spring and H3 buffer I successfully ran about 30 round of Federal M193 ammunition through the weapon with ZERO issues. Weather was high 80's, using Slip2000 lubricant and a standard full auto carrier and FN military contract bolt with copper spring and black insert.
For those worried about ejection patterns it was pretty consistent at about 300 o'clock. Since I already knew an H2 would work, based on other testing I skipped the BS and went straight to the H3. Obviously with full auto and burst it could be different, but since we know that the M855A1 is hotter something tells me that it is going to work just fine.
I have also built (2) M16A2 configuration uppers and when using the carbine lower receiver extension and a blue Sprinco spring with the H3 buffer and they also cycled with several types of ammunition with ZERO issues.
Thanks Gunz for confirming these findings.
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So a little follow up to this. Though not directly related this is some data I gathered from today. Maybe I missed it, but I was unable to find an exact weight of the H6 buffer.
H6 is 5.15 ounces. Right between an H2 and an H3.
H6 is 5.15 ounces. Right between an H2 and an H3.
Makes sense. If you're slicing the weights more, there's going to more spacers displacing the room for weights.
BufordTJustice
05-30-14, 20:07
wrong thread. FML.
I greatly appreciate the offer, however, we have found a solution with the H6s we could source on our base. I was able to find enough of them to outfit my Platoon with, so we are good to go at this time.
Thank you for the offer.
Sounds good, NYH1!
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