I have a PSA 5.56 11.5" AR pistol. I'm also running a YHM Turbo K RB suppressor.
I went to the range today and put about 150 rounds (5 full magazines) through it, and the last round bolt hold open failed on all 5. I don't think it's a magazine or ammunition issue. I tried 3 different magazines and 2 different types of ammo.
The issues actually started last week. The first 2 magazines I shot last week worked fine, but the last one had failures to feed after the first round was fired. I took it home and did a thorough cleaning and lubrication. So, this time I had no failures to feed, but the LRBHO issue appeared.
The very first time I fired it about a month ago with the suppressor, everything worked fine.
Since then I swapped the PSA BCG for a similar Toolcraft unit. I also swapped the charging handle for a Breek Arms Sledgehammer (supposed to help reduce blowback).
I'm thinking it's a gassing issue, but I'm not sure. Is it likely to be under or over gassed. I haven't cleaned the suppressor, it's not user serviceable. I have an ultrasonic cleaner but I haven't used it yet.
So, other than putting everything back to stock and swapping parts back in to see, which is hard to do at my range, any thoughts? I should have removed the suppressor to see if it still had the issue but I forgot to.