old-style primer seating tool vs. new

[Jeff Mayhew]

I decided to try out one of the older "pliers" style primer seating tools with RMC brass cases and standard 209 primers. I understand that the older tool is specifically for balloon-head cases, where pounding down on the inside base of the casing from above is not acceptable.

It works fine, and in fact has a nice positive seating feel (I prefer a grip-style primer seating tool for my regular cartridge reloading). However, it flattens the face of the primer considerably. See picture below; the left primer was seated using large "drift" pounded into the case from above, whereas the right primer was seated using the old "squeezer" tool.

Is this normal? Did the older primers have a different construction that avoided this? It seems very likely that it won't affect the function of the primer, but I'm just curious about whether this is normal, or the effect of using an "old" tool on "new" primers. Thanks!