LR308/AR10 Buffer Springs

[WillisB]

I am starting a LR308 build and im making a list of everything i want on the build. Im using an Areo Precision upper and lower, Faxon 18" Heavy fluted 5R match barrel with rifle length gas system (non adjustable block). Mil-Spec carbine length Buffer tube with an Odin Works AR-10 adjustable buffer. Rigth now im looking at the JP Tuned polished Extra power large frame carbine buffer spring. Of course i dont want it to short-stroke as if anyone does. Will this spring be two much if i using my buffer weighted at an H2 buffer? Should i use this stiffer spring or go with a more standard AR-10 strength spring?

 

[Twdmar]

What bolt carrier are you using, the aero? Are you building a 308? Small tweaks with the ar10 can create cycling problems. It's hard to know what results you will get without a few more details.

 

[WillisB]

What bolt carrier are you using, the aero? Are you building a 308? Small tweaks with the ar10 can create cycling problems. It's hard to know what results you will get without a few more details.

Right now im looking at the areo precision .308 BCG-Nickel Boron

 

[Twdmar]

Check out the JP lightweight one too. I have an aero and jp and the aero is quite heavy. I also had more problems tuning with the aero. I have run heavy buffers with standard springs in carbine stocks in two 308s with adjustable gas blocks.

 

[WillisB]

Check out the JP lightweight one too. I have an aero and jp and the aero is quite heavy. I also had more problems tuning with the aero. I have run heavy buffers with standard springs in carbine stocks in two 308s with adjustable gas blocks.

You mean a JP BCG?

 

[Sandstorm]

Adjustable gas block and JP Bolt Carrier were a absolute for my build...lets just say it didnt work well
until I got those...well at all. My story and your's may be different for sure.
AR10s are a strange animal to put together and get to work real smooth and cycle well.
Sure took me a while compared to everything id built before.

 

[Twdmar]

You mean a JP BCG?

That's correct. I'm not sure if you're doing a 308, they make one for 308 and a high pressure one that might work for 6.5 creed etc. It's a very nice part and way lighter than the aero.
I also have lightest weight 20" faxon barrels now. I had a medium weight 18" with the aero bcg and it was a pig.

 

[S3silver]

Adjustable gas block and JP Bolt Carrier were a absolute for my build...lets just say it didnt work well
until I got those...well at all. My story and your's may be different for sure.
AR10s are a strange animal to put together and get to work real smooth and cycle well.
Sure took me a while compared to everything id built before.

I definitely agree with this. My one AR10/AR308/LR308 (however you want to refer to them as) was definitely finicky to get to cycle right compared to my 4 ar15’s I pieced together. It seems the AR308 platform is over pressured to begin with so it takes a little more trial and error to get it to run right. For me the two main things were the adjustable gas block and a heavier buffer. These two things definitely made it easier to fine tune to the point where it cycles and runs good enough for me to leave it alone.

 

[Ray123]

Never had any serious trouble getting AR 10 cycling. I just use standard buffer and spring...with adjustable gas block, 6.5 Creedmoor, several 308 win., 358 win, 8.6 blackout, all work... only have heavy buffer on 9mm AR 15...everything else standard buffer and spring. An AR tells ya what it needs to work, gas port hole not big enough if it won't lock back on a normal pressure load with standard spring and buffer. Too zippy tweak the adjustable gas port...works for me..nice to use standard springs, buffers, and bolts available everywhere. N o special or expensive components needed. Use Tool Craft .065" firing pin for 6.5 Creed high pressure bolt, some have dual ejectors for in 308s win too...and center bolt carriers, true reciever face, glue in,..I have a lathe & mill to do this, but you can do what you can, to improve accuracy.
Example AR 10 308 win 18" proof SS barrel single load use Bobsled same high pressure load used bolt gun. 200 gr SMK 715 BC 2676 fps 18" AR 10...then close SA gas port 7 clicks and run 130 gr speer HP with 748 into 5 shot .3" and .4" back to back with LC brass and primers.

 

[Gino753]

Sorry to make another post but I’m trying to fish for as much knowledge as possible

I just took my first AR.308 build to the range the other day , and the build is

Aero Precision M5 Complete lower, With an VLTOR RE-10/A5 Buffer tube,

Tubbs Flatwire Rifle/Carbine spring
Aero precision 16” Upper with Aero precision factory installed adjustable gas block

And an 5.4oz H3 Standard length carbine buffer…

I got the rifle to run and cycle nice and smooth, and the bolt held open on the last round every time..However i had to open the Gas block to 11 Clicks to attain this, while the max the gas block is supposed to adjust too is 15 clicks open from closed

Is this satisfactory? Or should the gas block be closed more to get the rifle to run? Am I almost out of room incorrectly?

The complete lower, originally came with the Standard DPMS Buffer system, with the stubby 3.8oz buffer, and standard length buffer tube , and AR10 carbine spring

While I installed a heavier buffer, at 5.4oz and a A5 Buffer tube, roughly the length of the origional AR10 , and a heavier spring

 

[Andy Legg]

Sorry to make another post but I’m trying to fish for as much knowledge as possible

I just took my first AR.308 build to the range the other day , and the build is

Aero Precision M5 Complete lower, With an VLTOR RE-10/A5 Buffer tube,

Tubbs Flatwire Rifle/Carbine spring
Aero precision 16” Upper with Aero precision factory installed adjustable gas block

And an 5.4oz H3 Standard length carbine buffer…

I got the rifle to run and cycle nice and smooth, and the bolt held open on the last round every time..However i had to open the Gas block to 11 Clicks to attain this, while the max the gas block is supposed to adjust too is 15 clicks open from closed

Is this satisfactory? Or should the gas block be closed more to get the rifle to run? Am I almost out of room incorrectly?

The complete lower, originally came with the Standard DPMS Buffer system, with the stubby 3.8oz buffer, and standard length buffer tube , and AR10 carbine spring

While I installed a heavier buffer, at 5.4oz and a A5 Buffer tube, roughly the length of the origional AR10 , and a heavier spring

Sounds like you may be able to try a Standard Spring and cut back the gas block a little?

I have never tried one, but I like the A5 Buffer/Tube!!!

I could be wrong, but I do believe you should use an A5 Buffer as well…..You could damage your lower receiver using a Carbine Length Buffer if/when it bottoms out (it can’t due to the Carbine Buffer being too short)…the BCG will hit the Receiver. That’s if I understand the A5 Buffer System Correctly.

Andy Legg.

 

[Pawnee Bill]

Check in to JP Enterprises Silent Capture buffer set up. I use them in all my ARs.

 

[Gino753]

Sounds like you may be able to try a Standard Spring and cut back the gas block a little?

I have never tried one, but I like the A5 Buffer/Tube!!!

I could be wrong, but I do believe you should use an A5 Buffer as well…..You could damage your lower receiver using a Carbine Length Buffer if/when it bottoms out (it can’t due to the Carbine Buffer being too short)…the BCG will hit the Receiver. That’s if I understand the A5 Buffer System Correctly.

Andy Legg.

Firstly I wanted to Thank you for reaching out to me to offer me , parts to help me like that…It’s very much appreciated…with that said I’m going explain the whole A5 Buffer tube/AR.308 Thing…

So…there is the Armalite AR10, invented by Ugene stoner, The AR10 originally used a Longer carbine Buffer tube, versus the AR15’s carbine buffer tube.The AR10 also used a standard Carbine Buffer, the same one as an AR15…only at the heavier H3 Weight of 5.4oz, finished by an AR10 specific Rifle buffer spring.

The AR10 Buffer tube was originally 7 5/8” longe , where an AR15 carbine buffer tube is 7” long.

The Aero Precision M5 is an DPMS pattern AR10 Variant, I believe as was invented originally by panther arms, so the Aero M5 is that as well.It is not an AR10, But another form of an AR10 type rifle.Besides the AR10 and DPMS pattern rifle having different dimension receivers, the Aero M5 as most DPMS pattern rifles use a standard AR15 Carbine buffer tube..if the particular model is a collapsing stock model with a carbine buffer tube..The problem with this is that they use a .308 version of a carbine length spring ..They then take an Actual AR15 Carbine Buffer…Cut the height down on the buffer so that, the Longer .308 Bolt carrier can cycle all the way back, in the shorter 7” regular AR15 Carbine buffer tube.This way the rifle is able to work..

The issue however some people have is that , Dwell time is effected , using a stiff spring suitable to cushion a heavy .308 BCG, and this Stubby (Too Light) of a buffer, can cause BCG bounce, as the modified shorter Buffer system does not give the .308 bolt carrier time to breath and cycle.The result is a Faster Harsher cycle, if the rifle is able to work…I think proper barrel gas porting, might effect this as to why most of what I read about these DPMS pattern rifles is that they can be a pain to get working, in general as seems to be the common experience with them?

The A5 Buffer tube came out…to help the AR15 Cycle smoother, IMPROVE BCG TIMING…while giving the Marines the ability to have all this with a Collapsing stock… while having a closer to rifle length buffer system, as seems to be the most ideal system for both the AR15/AR10/AR.308….As the AR10 was originally invented with a Special Buffer tube made for it, more than likely to help its longer larger internals move in a more efficient manner as it was longer at 7 5/8” versus the AR15 Carbine buffer tube at 7”.

The A5 Buffer tube became adapted back and too the larger AR10/AR.308 system.However the Longer A5 Buffer that goes with this A5 Tube, won’t work with the AR10/AR.308 because the BCG is longer….see?

So too get this to work, people started installing the A5 Buffer tube on there DPMS pattern rifles ,along with an rifle length Buffer spring , however the choice for the buffer was to use an Actual AR15 Heavy buffer in the H2-H3 Format to allow enough room to remain in the A5 Buffer tube

So we are just bringing it back to its Roots, all in all the A5 Buffer tube/Buffer works fine in the AR15 as the shorter AR15 BCG works with the length of the A5 Tube and Buffer, but not with the longer AR.308 BCG

Sorry for my horrible Grammar..

 

[Oso]

JP Enterprise Silent Captured Spring - upgrade that’s worth the money.
https://jprifles.com/buy.php?item=JPSCS2-10

 

[Gino753]

JP Enterprise Silent Captured Spring - upgrade that’s worth the money.
https://jprifles.com/buy.php?item=JPSCS2-10

I have that in my AR15, I agree I love that system

I installed an Gieselle Super 42 in my other AR, and I don’t understand the issue..it moves stiff and crunchy


The Buffer tube as well, is a Gieselle and came in the kit all together, maby its something about how tight the inner diameter of the spring is too the buffer

But if you push on the buffer with your finger it’s kind of hard to push the buffer in, it fits loose in the buffer tube the assembly that is but it just cycles rough and feels like it’s grinding