AR-10 Buffer Question

BigMikey76 · March 18, 2019, 09:23 PM

I'm looking at purchasing a PSA PA-10. To save a few bucks, I'll be buying the upper and lower separately. The upper I want is an 18 inch .308 with a mid length gas system.
My question comes in on the purchase of the lower - some of them say they have a "standard heavy carbine" buffer, and some have a "PA-10 short" buffer. I have tried to look up the difference, but an hour of internet searches later, I am still confused. Which buffer should I get to make sure the rifle functions properly? For reference, I have put in links to the two types at the bottom of this post.
By the way, I would appreciate simple answers, if possible. I think part of my problem is that I just don't have the baseline knowledge and vocabulary to fully understand the articles I have been reading - they are largely written in technical language.

https://palmettostatearmory.com/psa-...165451341.html

https://palmettostatearmory.com/psa-...arth-fde1.html

riffraff · March 18, 2019, 09:41 PM

I don't understand the terminology there and am not familiar with PSA but here's what I think I know on AR10 ( term used loosely as there are all sorts of patterns ie LR308) buffers..

The DPMS pattern is a 7 inch buffer tube, which takes a short ( about 2.5 inch) buffer - this is shorter than a standard AR15 buffer and the springs are different too..

Other patterns use a longer buffer tube, which you can tell just by looking at them usually because a standard adjustable stock cannot fully close to the point where it touches the lower.. this is an AR15 sized buffer.. no idea on how springs are matched with these..

There are standard and heavy buffers, and springs, available in both styles.

I own both styles and the only thing I'd say is parts availability for buffers on the short style is limited- only 2 manufacturers make heavy buffers and only 1 (springco) has a decent heavy buffer spring I trust for the pattern.. in the pattern with the AR15 sized buffer you got lots of buffer options but not sure on springs.

Mobuck · March 19, 2019, 06:45 AM

If you buy a complete lower, it will have the correct buffer installed. Now, whether that buffer is the right weight for your purposes is another thing. From comments I've read, the AR 10 platform may suffer from "over gassing" even more than the 15 platform so an adjustable gas block may be a better answer than heavier buffers.
I've always been a proponent of adjustable gas blocks vs the "easy way out" of swapping buffers.

BigMikey76 · March 19, 2019, 07:28 AM

Mobuck- I've heard that, as well. Unfortunately, it's not available on the .308 models from PSA. I'll probably be adding one on at some point, since I am thinking about running a can, which makes adjustability even more necessary.

MarkCO · March 19, 2019, 10:31 AM

For .308s, heavy buffer (of the correct size, and there are several options) with a JP .308 flat wire spring (they make them in both lengths) and an adjustable gas block.

Buffers can have the weights removed and replaced, so I would not worry about it too much. Take what comes with the lower and then go about tuning it after you have shot a good 50 rounds through it.

Safestuffer · March 19, 2019, 10:01 PM

Watch for carrier overtravel. Pa10's with the longer buffer tube (not ar15 carbine length) are notorious for their assembled lowers being slightly off, with their buffer tube a little longer internally than it should be. Easy fix is to take the buffer and spring out and drop an appropriate number of quarters into the buffer tube until your bolt face clears the bolt catch by only 1/4" - 3/16" at full recoil. Otherwise you'll get impact marks on your lower at the receiver extension threads, if it's off. Hard fix is to take the buffer tube off the rifle and reshape the tube lip a bit so it can be turned another thread in the receiver before hitting the buffer detent. Mine has the quarters.

There are a lot of buffer tube/buffer combos but if you are getting a complete lower from psa, it should be correct as it comes, aside from the issue described above. Their longer buffer tubes ( 7 7/8" inside depth) are designed that length to accommodate a carbine length ar15 buffer at 3.25".

Buffer weight will depend on your preferences. Mine came with an H buffer. I switched to an H3 buffer and Tubb flatware spring because I reload and a heavier buffer and the right spring will add mass and resistance to the recoil system, which will delay the bolt from unlocking enough for pressures to be reduced, easing extraction and ejection. This is just a preference, my rifle ran fine as it came, although vigorously

BigMikey76 · March 19, 2019, 10:24 PM

Lower is ordered! I went for the one with the "standard heavy carbine" buffer. It comes with the Magpul ACS-L stock and their EPT (Enhanced Polished Trigger). I'm waiting for the upper that I want to become available, so it'll probably be a little while before I can give a range report.
Thanks for the answers - they were helpful, as always.

Jsnake711 · March 20, 2019, 08:54 AM

My pa 10 has standard h buffer. I also got an adjustable gas block which you really need, it'll tame some recoil and rubbe out the over gas and eject at 3 oclock. Make sure you get thr pa 10 buffer tube, my brothers had ar15 tube and the gun wouldn't cycle.

March 18, 2019, 09:23 PM	#1
BigMikey76 Senior Member Join Date: December 3, 2011 Location: Bellevue, NE Posts: 981	AR-10 Buffer Question I'm looking at purchasing a PSA PA-10. To save a few bucks, I'll be buying the upper and lower separately. The upper I want is an 18 inch .308 with a mid length gas system. My question comes in on the purchase of the lower - some of them say they have a "standard heavy carbine" buffer, and some have a "PA-10 short" buffer. I have tried to look up the difference, but an hour of internet searches later, I am still confused. Which buffer should I get to make sure the rifle functions properly? For reference, I have put in links to the two types at the bottom of this post. By the way, I would appreciate simple answers, if possible. I think part of my problem is that I just don't have the baseline knowledge and vocabulary to fully understand the articles I have been reading - they are largely written in technical language. https://palmettostatearmory.com/psa-...165451341.html https://palmettostatearmory.com/psa-...arth-fde1.html __________________ Some people are like Slinkies - not really good for anything, but you still can't help but smile when you see one tumble down the stairs. Last edited by BigMikey76; March 19, 2019 at 01:07 AM.

March 19, 2019, 07:28 AM	#4
BigMikey76 Senior Member Join Date: December 3, 2011 Location: Bellevue, NE Posts: 981	Mobuck- I've heard that, as well. Unfortunately, it's not available on the .308 models from PSA. I'll probably be adding one on at some point, since I am thinking about running a can, which makes adjustability even more necessary. __________________ Some people are like Slinkies - not really good for anything, but you still can't help but smile when you see one tumble down the stairs.

March 19, 2019, 10:31 AM	#5
MarkCO Senior Member Join Date: October 21, 1998 Location: Colorado, USA Posts: 4,308	For .308s, heavy buffer (of the correct size, and there are several options) with a JP .308 flat wire spring (they make them in both lengths) and an adjustable gas block. Buffers can have the weights removed and replaced, so I would not worry about it too much. Take what comes with the lower and then go about tuning it after you have shot a good 50 rounds through it. __________________ Good Shooting, MarkCO www.CarbonArms.us

March 19, 2019, 10:24 PM	#7
BigMikey76 Senior Member Join Date: December 3, 2011 Location: Bellevue, NE Posts: 981	Lower is ordered! I went for the one with the "standard heavy carbine" buffer. It comes with the Magpul ACS-L stock and their EPT (Enhanced Polished Trigger). I'm waiting for the upper that I want to become available, so it'll probably be a little while before I can give a range report. Thanks for the answers - they were helpful, as always. __________________ Some people are like Slinkies - not really good for anything, but you still can't help but smile when you see one tumble down the stairs.

March 18, 2019, 09:41 PM	#2
riffraff Senior Member Join Date: January 21, 2016 Posts: 629	I don't understand the terminology there and am not familiar with PSA but here's what I think I know on AR10 ( term used loosely as there are all sorts of patterns ie LR308) buffers.. The DPMS pattern is a 7 inch buffer tube, which takes a short ( about 2.5 inch) buffer - this is shorter than a standard AR15 buffer and the springs are different too.. Other patterns use a longer buffer tube, which you can tell just by looking at them usually because a standard adjustable stock cannot fully close to the point where it touches the lower.. this is an AR15 sized buffer.. no idea on how springs are matched with these.. There are standard and heavy buffers, and springs, available in both styles. I own both styles and the only thing I'd say is parts availability for buffers on the short style is limited- only 2 manufacturers make heavy buffers and only 1 (springco) has a decent heavy buffer spring I trust for the pattern.. in the pattern with the AR15 sized buffer you got lots of buffer options but not sure on springs.

March 19, 2019, 06:45 AM	#3
Mobuck Junior member Join Date: February 2, 2010 Posts: 6,846	If you buy a complete lower, it will have the correct buffer installed. Now, whether that buffer is the right weight for your purposes is another thing. From comments I've read, the AR 10 platform may suffer from "over gassing" even more than the 15 platform so an adjustable gas block may be a better answer than heavier buffers. I've always been a proponent of adjustable gas blocks vs the "easy way out" of swapping buffers.

March 19, 2019, 10:01 PM	#6
Safestuffer Senior Member Join Date: November 15, 2013 Posts: 101	Watch for carrier overtravel. Pa10's with the longer buffer tube (not ar15 carbine length) are notorious for their assembled lowers being slightly off, with their buffer tube a little longer internally than it should be. Easy fix is to take the buffer and spring out and drop an appropriate number of quarters into the buffer tube until your bolt face clears the bolt catch by only 1/4" - 3/16" at full recoil. Otherwise you'll get impact marks on your lower at the receiver extension threads, if it's off. Hard fix is to take the buffer tube off the rifle and reshape the tube lip a bit so it can be turned another thread in the receiver before hitting the buffer detent. Mine has the quarters. There are a lot of buffer tube/buffer combos but if you are getting a complete lower from psa, it should be correct as it comes, aside from the issue described above. Their longer buffer tubes ( 7 7/8" inside depth) are designed that length to accommodate a carbine length ar15 buffer at 3.25". Buffer weight will depend on your preferences. Mine came with an H buffer. I switched to an H3 buffer and Tubb flatware spring because I reload and a heavier buffer and the right spring will add mass and resistance to the recoil system, which will delay the bolt from unlocking enough for pressures to be reduced, easing extraction and ejection. This is just a preference, my rifle ran fine as it came, although vigorously

March 20, 2019, 08:54 AM	#8
Jsnake711 Member Join Date: January 18, 2019 Posts: 95	My pa 10 has standard h buffer. I also got an adjustable gas block which you really need, it'll tame some recoil and rubbe out the over gas and eject at 3 oclock. Make sure you get thr pa 10 buffer tube, my brothers had ar15 tube and the gun wouldn't cycle.