Primer issues

[Antonio m]

Hi,I am hoping to find information regarding firing pin strikes/ primer variables etc.
I sometimes see cratering on 270 win cartridge cases for no reason,the firing pin does leaves a shallower and smaller diameter strike on most primers than other rifles I have. It doesn't misfire but will crater on less than full power loads(sometimes).No extractor marks or tough ejection . Loads are chrono'd to confirm this.It is more prevalent with neck sized brass...but not always. Primers are not /unsafely flattened . This rifle is a newer BLR and I wonder if it.has something to do with the rebounding hammer? Anyways, I also wonder if an oversized flash hole or any primer make is more prone to this? I have tried several and magnum primers but don't see a definite pattern. Thanks for any insights...Tony

 

[CatShooter]

Hi,I am hoping to find information regarding firing pin strikes/ primer variables etc.
I sometimes see cratering on 270 win cartridge cases for no reason,the firing pin does leaves a shallower and smaller diameter strike on most primers than other rifles I have. It doesn't misfire but will crater on less than full power loads(sometimes).No extractor marks or tough ejection . Loads are chrono'd to confirm this.It is more prevalent with neck sized brass...but not always. Primers are not /unsafely flattened . This rifle is a newer BLR and I wonder if it.has something to do with the rebounding hammer? Anyways, I also wonder if an oversized flash hole or any primer make is more prone to this? I have tried several and magnum primers but don't see a definite pattern. Thanks for any insights...Tony

This is typical of rebounding firing pins - with a bolt gun, you have a heavy spring holding the pin in place against the primer so it can't push back until the pressures gets really high to overcome both the metal resistance, AND the spring - with a hammer (rebounding or not) there is no support to the indention so it can be pushed back at lower pressure.