Yeah, hard to diagnose this over the internet. Possibilities run from incorrect extractor, incorrect action spring, short chamber, incorrect locking seats, incorrect bolt, damaged or incorrect cam pin, damaged or improperly installed firing pin retainer, worn or damaged gas rings, Bent or damaged gas tube, clogged gas tube, mis aligned gas block, and even including an improperly tightened or loose barrel nut.

Just pop by the shop and we'll figure it out.