How dou you tell if new firing pin is neded?

Answer 1

You have more shot gun shells or bullets that fail to fire when you squeeze the trigger.

The primers on your spent cases are not very impacted. "You are seeing light primer strikes." What i do first is check the firing pin to see if it has a tiny hair line crack in it. And then I clean the firing pin and the bolt face with a old tooth brush. To remove any old burnt powder residue from around that area. And if that fixes the problem great!

If the shotgun or rifle still has the fail to fire problem and I have tried different types and brands of ammo then I replace it's spring's. Spring's get weaker with age and there cheap to replace. Most of the time the firing pin spring has just gotten to weak to drive the firing pin forward hard enough into the primer to set it off. Changing spring's also gives me a good excuse to clean the rifle or shotgun anyway. Good luck and good shooting.