Home Forums Hunting & Shooting AR and Tactical Rifles AR15 Pistol 9” 300blk Issues

I have a 300 blk pistol 9” barrel with an adjustable gas block and H2 buffer weight. Have adjusted the gas block its full range and have still not gotten the bolt to stay fully open after last round from magazine. Gun will also not chamber a second round as bolt is not moving all the way back. Should I test an H1 buffer weight? Could there be an issue with my gas block? This issue has arose with a variety of both subsonic and supersonic ammo.

I typically keep a range of buffers and buffer springs on hand. Everything from the standard carbine buffer up to an H3.
Same for springs. Everything from a Springco yellow, which is reduced strength, up to through their really stiff orange spring.

I mix and match until I find what works. And sometimes, you have to get out the drill and open up the gas port. It's a matter of figuring out what works in each situation.

It's always a possibility that your gas block could be misaligned or obstructed.

The first thing I would try though, is a standard weight buffer.

I'm running an H3 buffer in my 16" PSA upper (300BO). It's a pistol length gas system. I'm only shooting supersonic ammo, and it's running fine.

This ^^^
1) Try a standard weight (carbine) buffer
2) Check that your gas block is centered over the barrel's gas port
3) Verify gas port size

Always do one thing at a time so you can track what's going on with your troubleshoot.

Appreciate the insight got ahold of an H buffer. Will test this weekend!

Factory or reloads? Some powders that work great in a bolt gun won’t reliably cycle an AR.