Quote Originally Posted by Slippers View Post
308 ARs are finicky beasts, which is why Rich and I always preach factory guns. If you build one, though, you should absolutely use an adjustable gas block, gauge the chamber, and check the headspace.

Buffer/spring/tube configuration is always confusing, so just remember that a 308 carrier is longer. These combinations work together:

A5 buffer tube with H3 carbine buffer (NOT an A5H3 buffer) and Armalite EA1095 spring

Rifle buffer tube with Armalite AR10 rifle buffer (shorter than AR15 rifle buffer) and EA1095 spring.

DPMS also makes a shorter carbine buffer if you insist on using an AR15 carbine length buffer tube, but it's the worst possible combination.

The 308 BCG is bigger and heavier, so you need the armalite spring and a fairly heavy buffer to counteract it. I have never seen Slash's super heavy buffer help, though, and find it to be ridiculously overpriced. No use for sprinco springs, either.
Well, that's about as concise as an explanation of 308 buffer/spring/tubes as I've ever seen. FWIW, Aero uses the AR15 carbine w/ DPMS 308 carbine buffer I had no problems, but it is paired with an AGB. I use SLR Sentry AGBs on my two large frame builds (one Aero M5, one 2A Xanthos) and have been able to tune the gas for each reliably. Still waiting on my .30 cal can, though, so no comments for suppressed use, but I expect to dial the gas back a notch or two and be GTG.