I had a "problem", with my GAP-10. It's an early model, I picked up here, gently used. I broke speed limits, getting to the range. Had some surplus and hand loads, and started shooting. Failure to feed , to eject, stuck cases. First thought was I bought a lemon. Stupid. Checked my hand loads. Necked sized batch, for my bolt gun. Surplus shot OK, in the gun, but not on paper. Put her aside, for a long time (life got in the way). Finally got some time, and some Rl-15, And made up the loads the previous owner had kindly suggested, and OF COURSE, little groups, no problems, lesson remembered: Don't put cheap gas in a Ferarri.