After seeing a comment that heminut made about extractors. I looked at the extractors on the Brownells bcg's. There is a mark where they are running into the pin sig put in the barrel extension. I ordered a different extractor and it's almost 10 thousandths thinner than the ones I had in the guns. I am still having problems w/gun number 2 not always going into battery and leaving emptys in the receiver sometimes. I didn't get any pictures when I had it apart sorry. If the new extractor still hits that pin I'll pull the thing apart and knock the pin out.