assuming that all other parts of the process are correct and the problem is with the primers
is that the primer may not sat all the way down in the pocket. if you think about it, the anvil of the primer needs to be touching the bottom of the pocket. Do you think yours are.
how have they been stored, have they been kept dry?
I will share my opinion and my load data, BUT I am just a guy with too many cigars and too many guns. Whatever I say is probably wrong.