All this, and we still don't know anything about the equipment being used to seat those primers.
Lot's of reasons why thet're not seating below flush. The reason you suspect is NOT the reason, a magnum primer is NOT taller or thicker than a standard primer. You're simply NOT applying enough force to seat them deep enough.
Oh, and the bolt will NOT fire a primer that's out too far. That's what the firing pin is for, a sharp blow in the center of the primer cup.
The more people I meet, the more I love my dog
They're going to get their butts kicked over there this election. How come people can't spell and use words correctly?