Pierced primers in factory ammo

[Rotaxpower]

I have been shooting some Remington UMC 9mm and have been getting some pierced primers. Is this a ammo thing or is the firing pin to blame?

 

[FLHTCUI]

what gun are you shooting?
What is your cleaning regiment like?
I have no idea, but would suggest those might be a couple of pointers
more experienced shooters will need to help assist you in the problem.
Rob

 

[Lodi]

It could be either, or a combination of both.

What make and model of pistol are you using? What mods to the firing pin assembly have been done?

What have the fired primers looked like from other types of ammo?

 

[Rotaxpower]

I have been shooting them in a JR carbine, I clean it every time I get home with it. The mosti have shot it in one session is about 100 rounds.

 

[ATOM]

UMC is generally pretty good stuff. It's possible you got a bad lot of it, but it's more likely to be the firing pin.

Have you tried firing it from anything else? If you put 100 rounds through another 9mm and didn't get any, that would be suggestive.

Any pix?

 

[7mmlefty]

The firing pin has square shouldered due to lots of use or lack of tempering on the firing pin.