Is this happening with factory ammo, or with reloads? I ask because I recently ran into a problem with a batch of reloaded 7.5 x 55. Where the firing pin wouldn't even touch the primer. It appears the dies (lee) used were out of spec, pushed the shoulder back a few thousands too far.
I reload for over 50 calibers, and have never seen this before. So am suspicious that if you are having a similar issue (only not as severe) that it may be due to dies.