Firing pin hole has to be checked too.
There is a lot of pressure inside the primer cup. A revolver can have the hammer blown back to almost full cock with still a good indent showing in the primer. We took pictures of this happening before recoil started. We found double pin strikes on S&W revolvers, some outside the primer on the brass. This is why some .500's doubled, the hammer bounced back, cylinder unlocks and turns backwards and if there is a live round there the hammer will fire it.
If the pin is blown back, the cup will try to flow into the hole.
Bolt guns need a very strong mainspring for top accuracy. The worst thing to do with any gun is to reduce the hammer or mainspring, looking for a lighter pull.