I have a RRA 9mm upper that sits on a brand new Stag Arms lower with a Hahn bottom load magazine block and 9mm buffer. The bolt was ramped by a local black gun gunsmith. Prior to this incarnation, the upper was on a FA FN lower from work.
I've noticed that the upper, regardless of which lower its on, only runs 100% with 9mm NATO spec loads. It seems that the hotter the round is, the more reliable the weapon is. Worst luck has been with Winchester 147gr JHP. These induce classic short stroking symptoms. 115gr FMJs only fail occasionally but when they do, it looks like short stroking. I'm trying to get some +P+ JHPs and see if they run to verify my theory.
I was wondering if there's any way to make the gun more reliable with lower pressure rounds. I'd love to be able to run on it on Winchester White Box. I was wondering if I just need to break the gun in more or possibly ditch the 9mm buffer and try something a little less heavy.
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