Off-center primer hits, Shield

[smithers599]

Went to Scottsdale Gun Club today with a friend who was shooting a S&W .40 Shield. Occasionally, he would get a failure to fire. Inspection of the unfired cartridge showed striker hit on the very edge of the primer. (But without actually firing.) Fired cases showed the striker mark dead center on the primer.

This happened with several different magazines.

Any ideas what might cause this, and how to fix it?

Thanks.

 

[shooter444]

 

[shooter444]

On second thought,... you may have a broken firingpin that lines up sometimes, and sometime doesn't.

Pull the striker assembly, break it down and take a look. It is a very, very simple procedure.

I believe the breakdown can be viewed on YOUTUBE.

 

[smithers599]

Thanks. I will advise him to do that right now.
If the firing pin is hitting before the pistol is in battery, then it could be ugly if one of those edge hits actually ignites the primer.

 

[shooter444]

I can't foresee the pin striking before slide lockup..... because of a broken pin.

The striker will function as normal, with or without a broken pin (unless it is a very strange brake). The point of pin impact is what I think COULD be effected, upon firing, from a broken pin.

If he is just getting a pin smear emanating from the center of the primer, out to the edge of the primer, this could be normal for that weapon. I had a couple of early Steyr pistols that did it with both a 9mm and a 40mm. It functioned fine, accuracy was fine, but I just didn't like it and got rid of both.

JMO

 

[shooter444]

Got an update?

 

[smithers599]

Got an update?

You are not going to believe this. We met today at Scottsdale Gun Club. In preparation for removing the striker, he removed the slide -- and noticed a large clump of carbon on the extractor. I mean it was solid, like a piece of plastic. He chipped it off with a small screwdriver, then worked it over with a 22-caliber cleaning brush. Put it back together, and it runs fine now!

Hardened carbon on the extractor. Go figure. I learn something new every day.

 

[shooter444]

Interesting,... thanks!

 

[Viperdisorder]

He needs to clean more often, also avoid damn Winchester white box
If it's built up enough to carbonized, needs more cleaning

Thanks for the update to complete the story with a word to the wise

 

[Viperdisorder]

Yup, that's a lot of carbon, Winchester is horrible , white box is the worst