Buffers...I’m confused

[HanzMcFeely]

The LR308 build I finished up came with a Bushmaster 6 position carbine length tube/buffer/spring. Can’t seem to find any info on what this stock buffer weighs.

I picked up an odinworks adjustable buffer to install to help mitigate recoil. Now I’m second guessing it. Will it work and what should I set the starting weight at? Their chart on the website makes it even more confusing...

[HanzMcFeely]

Digging deeper:

Pulled buffer/spring back out and measured. It looks like it may be a bushmaster AR15 carbine set that CDNN included with this build kit.

Buffer measures 3.25”, spring measures 28/29 coils @ 11.5”, and the tube is 7.25”. If I can find a scale I’ll weigh the buffer

Looks like I may need to order a longer buffer tube and/or spring to go with the odinworks. And more weights.

The problem I’m finding is that with an empty mag inserted, the bolt will lock up on the back of the mag instead of at the bolt catch. Mag out and it locks up fine.

[Emptymag]

Longer buffer tube? Is that a real thing?

I don't know dick about 308 ARs, but thought they used the same tube as an AR15.

[God's Country]

Longer buffer tube? Is that a real thing?

I don't know dick about 308 ARs, but thought they used the same tube as an AR15.

One of the reasons I purchased a DPMS .308 was to avoid problems like this. I'm minimally knowledgeable about this stuff, and .308's seem to have less knowledge base, in general.



FWIW I swapped out the stock on my DPMS and the buffer tube (Brownells IIRC) because the DPMS is not mill spec on the diameter and the magpul stocks are mill spec.
The original tube was slightly longer than the replacement because of the angled butt end. The spring depth was the same. I checked an old bush master 5.56 tube and was identical to the .308 DPMS.

So in my case AFAIC the tubes are identical between platforms. No issues with the rifle.

[abner13]

One of the reasons I purchased a DPMS .308 was to avoid problems like this. I'm minimally knowledgeable about this stuff, and .308's seem to have less knowledge base, in general.



FWIW I swapped out the stock on my DPMS and the buffer tube (Brownells IIRC) because the DPMS is not mill spec on the diameter and the magpul stocks are mill spec.
The original tube was slightly longer than the replacement because of the angled butt end. The spring depth was the same. I checked an old bush master 5.56 tube and was identical to the .308 DPMS.

So in my case AFAIC the tubes are identical between platforms. No issues with the rifle.

My DPMS LR-308 had a short list of ammo NOT TO BE USED in the owner's manual. I've fired LOTS of US/Aussie/Brit/German/Portugese/Spanish/Swedish surplus 7.62x51 and commercial .308 with zero problems.

[HanzMcFeely]

Longer buffer tube? Is that a real thing?

I don't know dick about 308 ARs, but thought they used the same tube as an AR15.

Digging around online, from what I’ve read the armalite ar10 tube is longer.

[RRHemi]

DPMS platform LR 308's use a standard AR 15 buffer tube. I believe the buffer is shorter to accommodate a longer BCG. I just use those Buffers and tune with an adjustable gas block if needed. The spare springs I have bought are 308 specific.

[P89]

I ended up switching out springs and focusing less on the buffer weight (h3) to get the .458 to run right.
https://stratusarmament.com/product/...uffer-springs/

[HanzMcFeely]

DPMS platform LR 308's use a standard AR 15 buffer tube. I believe the buffer is shorter to accommodate a longer BCG. I just use those Buffers and tune with an adjustable gas block if needed. The spare springs I have bought are 308 specific.

That’s what I’m reading, and that the spring is 308 specific as well.

According to the chart at heavybuffers.com though, I may actually have an AR15 buffer.

[RRHemi]

That*s what I*m reading, and that the spring is 308 specific as well.

According to the chart at heavybuffers.com though, I may actually have an AR15 buffer.

My 308 Buffers are def shorter.