I bought an 1943 Standard Products M1 Carbine a few months back and just got out to shoot it today. I had a tone of feeding problems with all 3 types of ammo I tried to shoot (Prvi Partisan, Aquila, and Wolf). On top of that the bolt would not lock on almost every other shot and had to be slammed into place. Then after about 60 rounds the Hand Guard shot off and it seemed to cycle fine after that. I didn't see any marring on the hand guard that would point to anything rubbing. Any ideas??