On my mp5 I noticed last time I cleaned I could not get the locking piece out of the carrier it rotated fine and would go back together and function perfect F/A Semi. So I dropped in Sonic cleaner thinking it might be some carbon build up etc came out as clean as could be but still could not get the LP and firing pin and spring out. Put it back together still firing fine. So I got some Kroil in this week thought that might help let it soak seemed to free it up just a bit but still would not come out freely got a pair of channel locks and a screw driver and finally got it to come out a little then finally all the way. Cleaned inside the carrier and the LP till it looked new w/Kroil (some good stuff) Oiled it back up and now the LP wont go back in its like its too big took a hammer and same channel locks and forced/beat it back on/in turns freely and functions fine but wont come back out again. Anyone got any ideas? Am I missing something simple? any other bolt head and carrier and LP have always come out freely on all other guns........