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Ar 15 Buffer Tube and Spring on 308 Build?

GriffSniper

Private
Minuteman
Mar 8, 2020
19
5
Hi Guys,

I'm just about finished with my first DPMS 308 build and I've inspired my father to build one as well. However, my father decided to purchase a standard ar 15 buffer tube and buffer spring (without consulting me) to use on his 308. My question is, can you use a standard ar 15 carbine buffer tube and buffer spring (I believe stoner brand) on a 308 build? If so, what type of buffer weight should he use with that setup? Specific brand/model suggestions would be greatly appreciated.

On my build I used the Vltor A5 buffer tube, Armalite AR 10 EA1095 spring, and Vltor H3 buffer weight which I believe should work well.
 
Ar15 carbine tube is fine, BUT, you need to get the proper buffer. It limits you in weight, due to its size (and hot loadings), at only 2.5". I'd stuff a 30 cal carbine spring in there too. When I ran the setup (pretty sure it was all from Aero Precision in a package), my rifle worked great, and cycled fine. Until I wanted to get a little more oomph out of handloads. I think it's just plain ran out of ass. It only had 2 tungsten weights in it, with no room for more. Pretty sure the A5 system would let you at least use the ar15 length buffer, giving you more weight. Someone with more knowledge of the A5 can chime in on that. I swapped to a rifle tube and buffer, where I run a Magpul PRS, and never looked back
 
No, you can't use AR15 springs and buffers. The tube or receiver extension yes but I believe you always have to use a shorter AR10/LR308 buffer regardless. I don't think the Vltor buffer would work for me when I tested it on a .308 and ended up using it where it was intended, on a carbine gas AR15. You can buy a Tubbs flat spring or the like for .308 ARs or just buy an appropriate spring for .308, they used to not be hard to find before the panic buying. KAK makes a less expensive .308 buffer or you can always go with one from Slash, heavybuffersdotcom
 
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Interesting... one answer says you can with the right spring and weight, and another answer says you can't.
 
I linked the one I ran in my rifle above, definitely works. Dont go playing mismatch unless you know what you're getting into

Interesting... one answer says you can with the right spring and weight, and another answer says you can't.
 
For me ... I run both "pattern" carbine buffer setups on my Large Frame's .... I use 308 Tubbs Flatwire recoil springs in all setups, including my rifle stocked Large Frame AR's.

Which "pattern" you choose , is up to you. Both can be used.

"DPMS" pattern....AR15 Carbine length buffer tube, requires a 2.5" 308 specific buffer.

"Armalite" pattern..Vltor / 308 Armalite carbine length buffer tube, allows the use of AR15 carbine buffers.

Attempting to mix between the above guidelines.. will cause function issues.
 
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You can use a CAR-10 buffer from Slash/Heavy Buffers and a .308 carbine spring. I might happen to have one sitting around if you wanted to reach out.
 
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I have been searching for this for 6 months now! It is never in stock....Anywhere. any help out there please?
You can scare up a different RE elsewhere, but this would at least get you the correct buffer and spring:

EDIT:
If is the specific tube you need, mix and match kits:
 
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I have been searching for this for 6 months now! It is never in stock....Anywhere. any help out there please?
Vltor A5 buffer tubes and vltor a5h3 buffer weights have been coming in and out of stock on midway usa. The only part you'd be missing would be armalite ea1095 buffer spring which comes in stock every few months somewhere online (just search for it and enter info to be notified when in stock). That's what i did for my 308 builds.

Literally just bought the tubes and weights a few weeks ago. Waiting on the springs now.
 
Clint at Heavy Buffers is who/whom you seek.

He has walked me through:
ARMALITE 308/762/6.5CM
AP M5E 6.5CM with BA/PR/Dragos pipe 22"-24" pipe
458/375/358 SOCOM
pushing two (2) decades
 
You can scare up a different RE elsewhere, but this would at least get you the correct buffer and spring:

EDIT:
If is the specific tube you need, mix and match kits:
Thanks a ton. Got to finish my build and I'll buy tv free new RE in time.
 
AR308 buffer should be 5.4oz weight minimum. (NOT 3.8oz) I used a Sprinco "Orange" spring and a KAW Valley 5.6oz buffer in my PSA build.

If you have a STD AR15 buffer tube it should have an internal depth of 7 inches. This 7" internal depth tube requires a shorter buffer for .308. The buffer length should be 2.5".

Slash's Heavy Buffers would be your best/easiest route. He can fix you up.

If you want a hardcore no-BS education about this, go here:
And pay close attention to your gas tube length as well. It's explained in the threads above and will solve many cycling issues.

Oh, also, even if you use the proper length buffer for .308, the std AR15 spring won't compress enough to allow the bolt to come back far enough to lock on an empty mag. I learned all this the hard way........
 
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Good info in here

As far as Aero Precision shortages........could be because they recently moved locations for at least some parts of the business.

I havent found an M5 R-one or M5 S-One in stock ANYWHERE since November. I'd prefer R-One M-Lok for an M5 .......it's a mythical beast nowadays.
 
This kit right here. Comes with a H-3 but lets you run whatever AR-15 length buffer you want. The collapsible butt stock will be about 0.75" from the lower receiver. Works great for me. It's also in stock.