Buffer for 20" AR15?

DubC-Hicks · February 2, 2012, 09:27 PM

Hey guys, I just bought a 20" rifle length PSA 5.56 upper for my Spikes Carbine lower. What buffer and spring set-up can I run to get the smoothest/softest recoil possible but still keep the rifle from short-stroking? I mostly run 62gr and 55gr surplus BTW.

wnycollector · February 3, 2012, 05:41 AM

I run a 20" rifle upper on a Cav Arms MKII lower that has a standard weight carbine buffer in it. That setup is very reliable even lower powered Russian steel case ammo.

madcratebuilder · February 3, 2012, 06:18 AM

The rifle length gas system shoots fairly soft compared to the carbine length system. I would start with a standard carbine buffer and spring. You could try a H buffer if you have one. it may short stroke on low power loads.

RT · February 3, 2012, 06:25 AM

I believe the Canadians use a H2 buffer in their C7A2 rifles. Regardless, carbine or H buffer would probably be your best bet.

DubC-Hicks · February 6, 2012, 07:13 PM

Alright, so I went out and shot it again so I can see where the brass is landing. I was using the ST-T2 buffer and carbine spring that came with the lower.

With AE .223 55gr, it is ejecting at 2 o'clock about 7 feet. And with 62gr surplus, it is ejecting at about 1 o'clock about 7-8 feet. To me, it seems like I would need a heavier buffer/spring. Is this correct? Do you guys think a ST-T3 would work fine? Or do I just need to swap to a stiffer spring and keep the ST-T2? Or do you think I need both a heavier buffer and stiffer spring?

Thanks for the suggestions so far.

dvdcrr · February 6, 2012, 08:04 PM

Why are you not using a rifle buffer do you have a collapsible stock? If you have a collapsible stock, just stick an H buffer in there and be done with it.

Willie Lowman · February 6, 2012, 08:08 PM

I'd get full length buffer and a A1 or A2 stock. It's amazing how well these rifles work when you shoot them in their intended configuration.

DubC-Hicks · February 6, 2012, 08:14 PM

dvdcrr, yes, I am using a collapsible stock. And I don't think an H buffer would be heavy enough, since the ST-T2 I'm using now doesn't seem to slow down the BCG enough. That's why I asked about the ST-T3. I'd like to slow the BCG down enough to get it to eject around 3 o'clock with 62gr surplus, so the rifle isn't getting beaten up as much.

CTS · February 6, 2012, 09:08 PM

I think Willie has the best idea but, if you want to keep the carbine stock then yes, I'd try the T3 buffer.

madcratebuilder · February 7, 2012, 08:49 AM

Quote:

Originally Posted by DubC-Hicks

I am using a collapsible stock. And I don't think an H buffer would be heavy enough,

Using a rifle length gas system with a 20" barrel on a carbine lower I have never had to use anything more than a H buffer. My 18" rifle length gas system runs very well with the standard carbine buffer. YMMV

DubC-Hicks · February 7, 2012, 04:39 PM

I've been doing some more research about this, and a lot of people say to keep the lighter buffer and just get a heavier spring. Does this make sense? If this is the case, do you guys know how a Sprinco Blue or Red would work?

madcratebuilder · February 8, 2012, 11:20 AM

I have a Sprinco Blue spring and ST-T2 in my 10.5 sbr, this combo works well both lower power .223 and full power xm193

I like to use the heaviest buffer that well allow normal function of the gun with the ammo I normally shoot. I normally use a standard spring.

Here are the buffer weights in case you don't have them. These weights have a +/- of .1oz.

Carbine= 2.9 oz -> 3 steel weights
H buffer= 3.8 oz -> 1 tungsten weight
ST-T2= 4.3oz. -> tungsten powder
H2 buffer= 4.6 oz -> 2 tungsten weights
ST-T3= 5.4oz -> tungsten powder
H3 buffer= 5.6 oz -> 3 tungsten weights

Rifle buffer= 5.2oz
The ST-T3 is very close to the rifle weight.

Vltor A5 RE system. The Vltor buffers requires the Vltor A5 RE.
Vltor standard A5 buffer weighs 5.3 oz
Vltor H3 A5 buffer weighs 6.1oz
Vltor H4 A5 buffer weighs 6.8oz

I have the A5 behind a 6.5 Grendel, 5.3oz buffer and it's a very smooth shooting rifle. I'm not going to run out and replace my existing M4 RE's but if I ever need to buy a RE it well be the A5. It's that much better. You can use any mil-spec butt with the A5 RE, it well not close all the way because the A5 is longer than the M4 RE's.

If you have been looking at that case ejection chart that's floating around use it as a general guide, it's not a dyed in the wool spec. Ejection pattern is second to function. Both extractor tension and ejector spring effect the ejection pattern.

YMMV

DubC-Hicks · February 9, 2012, 07:07 PM

Thank you for the buffer weights. So I think I'm going to try the Sprinco blue first since it's cheaper than a buffer, and if it doesnt help/work, I'll try a Spikes T3. Thanks for the help guys.

February 2, 2012, 09:27 PM	#1
DubC-Hicks Senior Member Join Date: December 20, 2009 Location: Backwoods, Northern MI Posts: 1,034	Buffer for 20" AR15? Hey guys, I just bought a 20" rifle length PSA 5.56 upper for my Spikes Carbine lower. What buffer and spring set-up can I run to get the smoothest/softest recoil possible but still keep the rifle from short-stroking? I mostly run 62gr and 55gr surplus BTW. __________________ ”Gun control is like trying to reduce drunk driving by making it tougher for sober people to own cars.” ~Unknown

February 6, 2012, 07:13 PM	#5
DubC-Hicks Senior Member Join Date: December 20, 2009 Location: Backwoods, Northern MI Posts: 1,034	Alright, so I went out and shot it again so I can see where the brass is landing. I was using the ST-T2 buffer and carbine spring that came with the lower. With AE .223 55gr, it is ejecting at 2 o'clock about 7 feet. And with 62gr surplus, it is ejecting at about 1 o'clock about 7-8 feet. To me, it seems like I would need a heavier buffer/spring. Is this correct? Do you guys think a ST-T3 would work fine? Or do I just need to swap to a stiffer spring and keep the ST-T2? Or do you think I need both a heavier buffer and stiffer spring? Thanks for the suggestions so far. __________________ ”Gun control is like trying to reduce drunk driving by making it tougher for sober people to own cars.” ~Unknown

February 6, 2012, 08:08 PM	#7
Willie Lowman Senior Member Join Date: March 5, 2009 Location: Uh-Hi-O Posts: 3,006	I'd get full length buffer and a A1 or A2 stock. It's amazing how well these rifles work when you shoot them in their intended configuration. __________________ "9mm has a very long history of being a pointy little bullet moving quickly" --Sevens

February 6, 2012, 08:14 PM	#8
DubC-Hicks Senior Member Join Date: December 20, 2009 Location: Backwoods, Northern MI Posts: 1,034	dvdcrr, yes, I am using a collapsible stock. And I don't think an H buffer would be heavy enough, since the ST-T2 I'm using now doesn't seem to slow down the BCG enough. That's why I asked about the ST-T3. I'd like to slow the BCG down enough to get it to eject around 3 o'clock with 62gr surplus, so the rifle isn't getting beaten up as much. __________________ ”Gun control is like trying to reduce drunk driving by making it tougher for sober people to own cars.” ~Unknown

February 7, 2012, 04:39 PM	#11
DubC-Hicks Senior Member Join Date: December 20, 2009 Location: Backwoods, Northern MI Posts: 1,034	I've been doing some more research about this, and a lot of people say to keep the lighter buffer and just get a heavier spring. Does this make sense? If this is the case, do you guys know how a Sprinco Blue or Red would work? __________________ ”Gun control is like trying to reduce drunk driving by making it tougher for sober people to own cars.” ~Unknown

February 3, 2012, 05:41 AM	#2
wnycollector Senior Member Join Date: April 22, 2007 Posts: 1,996	I run a 20" rifle upper on a Cav Arms MKII lower that has a standard weight carbine buffer in it. That setup is very reliable even lower powered Russian steel case ammo.

February 3, 2012, 06:18 AM	#3
madcratebuilder Senior Member Join Date: November 2, 2007 Location: Northern Orygun Posts: 4,923	The rifle length gas system shoots fairly soft compared to the carbine length system. I would start with a standard carbine buffer and spring. You could try a H buffer if you have one. it may short stroke on low power loads.

February 3, 2012, 06:25 AM	#4
RT Senior Member Join Date: September 9, 2000 Location: San Antonio, TX Posts: 2,194	I believe the Canadians use a H2 buffer in their C7A2 rifles. Regardless, carbine or H buffer would probably be your best bet.

February 6, 2012, 08:04 PM	#6
dvdcrr Senior Member Join Date: July 5, 2010 Posts: 665	Why are you not using a rifle buffer do you have a collapsible stock? If you have a collapsible stock, just stick an H buffer in there and be done with it.

February 6, 2012, 09:08 PM	#9
CTS Senior Member Join Date: November 6, 2011 Location: NE Georgia Posts: 1,070	I think Willie has the best idea but, if you want to keep the carbine stock then yes, I'd try the T3 buffer.

February 8, 2012, 11:20 AM	#12
madcratebuilder Senior Member Join Date: November 2, 2007 Location: Northern Orygun Posts: 4,923	I have a Sprinco Blue spring and ST-T2 in my 10.5 sbr, this combo works well both lower power .223 and full power xm193 I like to use the heaviest buffer that well allow normal function of the gun with the ammo I normally shoot. I normally use a standard spring. Here are the buffer weights in case you don't have them. These weights have a +/- of .1oz. Carbine= 2.9 oz -> 3 steel weights H buffer= 3.8 oz -> 1 tungsten weight ST-T2= 4.3oz. -> tungsten powder H2 buffer= 4.6 oz -> 2 tungsten weights ST-T3= 5.4oz -> tungsten powder H3 buffer= 5.6 oz -> 3 tungsten weights Rifle buffer= 5.2oz The ST-T3 is very close to the rifle weight. Vltor A5 RE system. The Vltor buffers requires the Vltor A5 RE. Vltor standard A5 buffer weighs 5.3 oz Vltor H3 A5 buffer weighs 6.1oz Vltor H4 A5 buffer weighs 6.8oz I have the A5 behind a 6.5 Grendel, 5.3oz buffer and it's a very smooth shooting rifle. I'm not going to run out and replace my existing M4 RE's but if I ever need to buy a RE it well be the A5. It's that much better. You can use any mil-spec butt with the A5 RE, it well not close all the way because the A5 is longer than the M4 RE's. If you have been looking at that case ejection chart that's floating around use it as a general guide, it's not a dyed in the wool spec. Ejection pattern is second to function. Both extractor tension and ejector spring effect the ejection pattern. YMMV

February 9, 2012, 07:07 PM	#13
DubC-Hicks Senior Member Join Date: December 20, 2009 Location: Backwoods, Northern MI Posts: 1,034	Thank you for the buffer weights. So I think I'm going to try the Sprinco blue first since it's cheaper than a buffer, and if it doesnt help/work, I'll try a Spikes T3. Thanks for the help guys. __________________ ”Gun control is like trying to reduce drunk driving by making it tougher for sober people to own cars.” ~Unknown

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