Please tell me what's wrong with my rifle
it's a 12BR. I did a ladder test with Berger 105 hybrids. Powder is N150 CCI BR4 primers, about .010" jump. I started exactly with what Berger states in their manual, 27.5g with a .3g increment up to 30.2g which is less the the max load in the book. here's the problem. well into the test, but before getting anywhere near my max load, I'll start getting very heavy bolt lift for a few shots and then it will stop. I'll progress up to heavier loads and it will happen again for one or two shots and then stop again. I managed to get up to the max load and bolt lift/extraction was fine but I suspect, had I kept shooting , eventually it would happen again.
My loading equipment is Forster Coax, Redding Type S dies, Cambridge FX201 scale. The rifle has been bedded, SSS ejector, bolt lift kit from Stockade. Barrel is a Criterion from Northland. PTG go and nogo gauges used.
this sort of thing happens with other, known good loads also.
Al