Hey guys looking for some advice. Took my 300 blk 16" carbine gas with standard buffer and FA BCG out. Noticed it would not lock back after final round 50% of time. Also seems like it's short stroking. The casing from the fired round would not eject and would still feed another round. That happened probably around 6 out of 30 times. I was shooting some ammo from good to go, it's a 147gr. Non suppressed. Any ideas?