I've noticed this problem before, especially with W-W primers. I observed the leading edge of the primer was rough and interfered with seating. Whether the plating was not controlled, the forming die for the shaping was worn, or the cut primer blank before forming was worn and rough would be hard to tell. The uneven edge could allow gas leakage. Once the case started into the pocket, there was no more than "normal" resistance.
I sort brass by brand and attempt to get it sorted by lot number if new brass. Three hundred cases are allocated to each match rifle since a two-day Regional Match or the Nationals need the reserve loads for sighting.
In this day of shortages, I am using Federal primers on all loads except Alice's .308 since we started that load with W-W primers. There is strict primer rationing at the Hyett household. Once I am out of Federal Large Rifle, the loads will be exclusively W-W since that is what I will have left.
Hopefully, there will be primers available at reasonable prices by the Fall of 2022.
Farm boy from Illinois, living in the magical Pacific Northwest