Question: A5 buffer system vs. 5.56/.300BLK SBR's

Looking for some input from those with experience.  BLUF, I got my SBR stamp back.  I have both a 11.5" LMT MRP in 5.56 and a 9" AAC 300BLK upper for the SBR.  I also like to hunt with my rifles, so I want to hunt whitetails with the Blackout.  We can talk hunting ballistics in another thread, not needed here.  Per DNR regs, it's ok to hunt with an SBR but minimum overall rifle length is 26".  With an adjustable stock on a "normal" length carbine buffer tube, I'm at 25.5" OAL.  Changing to an A5 setup should gain me an extra 3/4" which solves the OAL problem.  However, I would prefer to buy one buffer and am wondering what weight to go with.  Anyone happen to have experience with the A5 and those two calibers?  To muddy the waters even more, what if I want to shoot the Blackout suppressed (not for hunting at least now).

Thanks

"These are the rules. Everybody fights, nobody quits. If you don't do your job I'll kill you myself."

 

Joined: 04/01/2004     Location:  Twin Cities, MN

Original Post

Why don't you just use a buffer tube spacer? It allows for carbine buffers and springs to be used in rifle length buffer tubes. 

"Fighting Power", in brief, is defined as the sum total of mental qualities that make armies (or men) fight. Martin van Creveld

I like the A5 system.  I use in all but my HK's or the factory KAC.

The A2 (one in the middle) is the standard (not sure if that's what Kev meant to say).  The 5 buffers numbering 0-4 is a little confusing.

H0 : 3.8oz

H1: 4.56oz

H2: 5.33oz

H3: 6.08oz

H4: 6.83oz

The H4 is mostly for over-gassed and suppressed piston guns like the early 416 10.4's.   I would think you could find a happy medium in the H2 or H1.  The only problems I've seen are when people try to run a heavy H2 or H3 on the A5 system on a properly gassed (not overgassed like most) gun shooting weak ammo and with goofy shit like an LMT enhanced carrier and they have no juice left to cycle the gun. 

 

"Pain, we endure...faulty weaponry, we do not."

FYI BCM sells the A5H0 as the default buffer, while Vltor's default is the A5H2.  Some good info from M4C:

https://www.m4carbine.net/show...or-this-list-of-guns

You can also experiment and creat your own buffers if you have spare weights and want to dissect your buffer:

A5H0: 0 tungsten, 4 steel
A5H1: 1 tungsten, 3 steel
A5H2: 2 tungsten, 2 steel (standard/stock buffer)
A5H3: 3 tungsten, 1 steel
A5H4: 4 tungsten, 0 steel

Thanks for the info guys.  Turns out that there's enough length difference between my old VLTOR stock and a Magpul ACS that I had laying around that it puts me over the 26" OAL minimum required by hunting regs.  Slightly heavier but not enough to be concerned about.  Based on some of the info here though I may look into the A5 down the road.

"These are the rules. Everybody fights, nobody quits. If you don't do your job I'll kill you myself."

 

Joined: 04/01/2004     Location:  Twin Cities, MN

pointblank4445 posted:
The only problems I've seen are when people try to run a heavy H2 or H3 on the A5 system on a properly gassed (not overgassed like most) gun shooting weak ammo and with goofy shit like an LMT enhanced carrier and they have no juice left to cycle the gun.  

There are a lot of people on m4carbine.net running H3 buffers with the LMT enhanced carrier and not having any problems.

I run that combo in both my rifles without any issues.

Joined: 3/27/09          Location: Back in MA for now

EzGoingKev posted:
pointblank4445 posted:
The only problems I've seen are when people try to run a heavy H2 or H3 on the A5 system on a properly gassed (not overgassed like most) gun shooting weak ammo and with goofy shit like an LMT enhanced carrier and they have no juice left to cycle the gun.  

There are a lot of people on m4carbine.net running H3 buffers with the LMT enhanced carrier and not having any problems.

I run that combo in both my rifles without any issues.

There's a lot of folks there too that don't know their ass from a hole in the ground too...  Point being, I don't take what's going on there as gospel.

Not saying those 2 things can't go together, but tolerance stacking comes back to bite some people.  In a world of 3-gun AR's that barely spit out brass to 16" carbine guns, there's plenty of middle ground to work with.  I tend not to push the envelope too hard either way.

"Pain, we endure...faulty weaponry, we do not."

pointblank4445 posted:

Not saying those 2 things can't go together, but tolerance stacking comes back to bite some people.  In a world of 3-gun AR's that barely spit out brass to 16" carbine guns, there's plenty of middle ground to work with.  I tend not to push the envelope too hard either way.

So what combo of A5 parts/enhanced carrier/ammo did you try that gave you issues?

Joined: 3/27/09          Location: Back in MA for now

EzGoingKev posted:
pointblank4445 posted:

Not saying those 2 things can't go together, but tolerance stacking comes back to bite some people.  In a world of 3-gun AR's that barely spit out brass to 16" carbine guns, there's plenty of middle ground to work with.  I tend not to push the envelope too hard either way.

So what combo of A5 parts/enhanced carrier/ammo did you try that gave you issues?

 18" rifle, H3, Springco Green w/ Black Hills blue box .223 77gr.   This was with the enhanced bolt as well; so it's still unclear if the bolt or carrier was at fault.  Milspec bolt group cleared up most of the problems.  Subsequent 18" rifle length guns with H2, Springco Greens have eaten the same ammo even down into bitter winter temps.  

 

"Pain, we endure...faulty weaponry, we do not."

FWIW, I have shot the hell out of an 11.5" suppressed SBR with a VLTOR A5/A5H2.  I have had zero problems with this and have shot it extensively for several years now, and I think I actually cleaned it once or twice.....I have a 18" barreled gun that has been used to hunt deer/hogs for the last couple of years with the same setup, no issues there either.  Not all that high of a round count, but it's been reliable.   I just recently put that same system on another 14.5" gun but really haven't got to shoot it other than a few rounds to zero.  I have a few other guns I plan to put it on, I like them a lot.   I've shot everything from 55 gr. ball (whatever my agency has at the time) to quite a bit of Black Hills 77 gr. without issues.  

*******

Joined 08/26/03   Location:  Southern Oklahoma

pointblank4445 posted:

 18" rifle, H3, Springco Green w/ Black Hills blue box .223 77gr.   This was with the enhanced bolt as well; so it's still unclear if the bolt or carrier was at fault.  Milspec bolt group cleared up most of the problems.  Subsequent 18" rifle length guns with H2, Springco Greens have eaten the same ammo even down into bitter winter temps.  

The enhanced bolt seems to be pretty finicky if you veer away from what it was specifically designed for.

I run the LMT FA enhanced bolt carrier with BCM bolts, H3 buffers, and Sprinco green action springs in both rifles.

One is a Colt 6920 with the carbine length gas system and the other is a rifle I built using a DD 16" barrel with a mid-length gas system. I have fired a few thousand rounds through them without any issues.

I shot some PMC bronze through them to see how they cycled weak ammo. They functioned 100% in the summer heat of MA and OK. I also ran them in single digit weather in MA during a few snow storms, they still functioned 100%. 

 

Joined: 3/27/09          Location: Back in MA for now

EzGoingKev posted:

The enhanced bolt seems to be pretty finicky if you veer away from what it was specifically designed for.


 

Yeah, I get that.   It's not a problem I run into anymore with the gas systems I use. 

"Pain, we endure...faulty weaponry, we do not."

I have used the A5 RE, A5H2 and Sprinco green spring with 5.56 11.5" uppers, suppressed & unsuppressed, to good effect. I also get good results with a carbine RE and an H or H2 buffer. Both work well, but I have a preference for the A5 system.

Just because it's rocket science doesn't mean it's complicated

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