Hello, I have finished my first .308 AR build and it has feeding problems, hopefully someone here can help.
It's an Aero Precision M5E1 complete upper, 20" barrel. DPMS compatible 80% lower, Aero Precison LPK, Aero Precision BCG and charging handle. The buffer, spring, and receiver extension are all from Heavy Buffers, it's an AR10R-XH buffer, EA1095 spring, and rifle-length extension. The stock is a Magpul PRS Gen 3.
So the problem it has is that when a 20 round mag is loaded with more than about 10 rounds, the round fails to feed. The round will end up about halfway out of the mag and pinched in between the bcg and the chamber, I have attached some pictures so that you can see what I mean. With 10 rounds or less it seems to be happy and has no feeding problems. I have tried Magpul Gen 3 magazines and also Lancer L7 magazines and they both experience this problem. I have tried Sellier & Bellot 147gr NATO rounds and I have also tried some hand-loads that I am not sure of the specs, and both types of rounds experience this problem. I am also seeing what I think are lots of brass flecks in the chamber.
Any suggestions?