THIS ARTICLE IS GOING TO TALK ABOUT BUFFERS IN THE 308AR ARENA
For starters because the 308AR never took on a mil-spec standard like the AR-15/ M4 has. This has thus caused many head aches for 308AR owners over the years. However, as of today it would seem there is some clarity. There are 2 basic receiver designs in the market: DPMS and ARMALITE AR10/ SR25. There is also the newer small framed 308s like the POF Revolution, but for the context of this article I will leave that alone.
When Armalite launched the AR10 they used a "long" mil-spec buffer tube, where DPMS released their AR308 using a AR15 mil-spec buffer tube. The AR10 used a AR15 (H3) carbine buffer and DPMS used a shortened buffer.
Most of the market today is made up of these 2 designs. We decided to run with the DPMS AR308 receiver design (originally) because the AR10 ran a different magazine, which did not offer a magwell sized optimal when compared to the DPMS/ SR25. It is our understanding Armalite has started offering a AR-10A model which will accept our magazines, so we are working on design for a Armalite GEN-12 upper.
That all said when we set out to build a 12 gauge AR we used the spec of the time, which was DPMS GEN1. All of the GEN12 uppers and shotguns run the DPMS short buffer and AR15 carbine length tubes.
So if you are building a lower for a GEN-12 upper or looking to fine tune your GEN-12, then you need to understand the short DPMS buffer and a H1 AR15 carbine buffer both weigh about the same (~3.0oz and ~3.8oz respectively). Typically an Armalite 308 buffer kit comes with a H3 buffer weight (~5.4oz), and it may not reliably cycle light loads like bird or target, but it is a easy fix! Just switch out the H3 buffer with a H1 buffer.
Ultimately, the shooter needs to pick a good buffer weight and design based your shooting needs. We have found both buffer kits will work, but you will need to make a selection based on your 12 gauge shell choice and/ or 308 needs.
In conclusion if you run a DPMS 308 short buffer kit then you may want to get a heavy buffer to run magnums and hotter loads to help absorb the recoil, decrease abuse to both the shooter and the weapon. If you run a Armalite buffer kit then you may want to have several buffers or get a customization buffer kit like that from KAK Industries for your shooting needs.
Leave your questions in the comments.