Either the pressure is enough to flatten a primer, or it isn't ( all else being equal) if that isn't the case, I would love to why.
How much pressure does it take to flatten a primer, and are all primers equally resistant to deformation?
THAT would be good to know. I know that primer cups differ in thickness and have different properties. That is why I said "all else being equal." I also know that headspace plays a role in primer flattening. I have seen write ups correlating case head expansion to pressure, but I have never seen anything on primers in controlled conditions.
