Thread: New barrel vs New rifle conundrum

Ok, so a couple of questions.

Is the issue you are concerned about headspace ? Flat primers without heavy bolt lift is more a sign of headspace issues than pressure to me.

Or are you suddenly seeing MV changes ?

Are you full length sizing or neck sizing only ? Do a shoulder measurement of a fireformed case.

Repeat the test with your usual bench setup, preferably sturdy front and rear rests.