I know the answer to this question already, but I thought putting it here might help somebody out later on. And have some fun figuring it out.
About the gun. It was bought brand new. It only ever had sig 100gr .380 ammo fired from it. Approximately 350 rds when the problem started. Was always ran wet.

Add ons I did myself were laser,(under frame attached to trigger guard), hogue rubber grips.
Lgs added a set of new sights made by speed sights.
What started happening: load a fresh magazine release slide catch pistol would go to full battery. Click. Press checked,rnd is in chamber. Manually cock the hammer and pull the trigger, bang. I removed the mag ran the slide manually a few times everything seemed fine. This time I load the mag pulled the slide and pistol went into battery. Pulled the trigger. Click. Recocked the hammer manually, bang.
I brought it home took it apart cleaned and oil the snot out of it. Didn’t see anything out of whack. Took it back to range. Loaded mag released the slide...click, cocked the hammer manually, click. Now it’s just putting light primer strikes on the rounds. Tried 4 more rds, no joy and had the light strikes. Sent it to sig for repair...got it back today.
What was wrong with this pistol?

Moved from the lounge.

Thanks arc...

No papa ..not polish feed ramp

quote:

Originally posted by Jimg1960:
What was wrong with this pistol?

Too much lube/gunk in the firing pin channel?

Not to much lube or gunk..

quote:

Originally posted by Jimg1960:
Not to much lube or gunk..

Damaged or defective mainspring?

No the Main spring is fine.

Give us a clue. Did the pistol receive or come new with the factory safety upgrade?

No work was done on the pistol except what I put in the write up. The answer is in the write up..sorta

Was it SIG ammo related?

No. Not ammo , but that’s what I thought for while.

Not the grip work.

Clue: it is a normal gun part related issue but not the guns fault..

Did the sight installation somehow impede the firing pin?

the firing pin block safety spring was not in the gun. It is located under the rear sight

Sig replaced it for free...

Good deduction work hjs...lol

quote:

Originally posted by Jimg1960:
Good deduction work hjs...lol

It's good to know SIG addressed the problem for you on their dime. Thanks!

When I read the report I thought that as well, they surely didn’t have to do that. That spring is sitting somewhere on my lgs work bench. I do wonder how it fired at all becoming progressively worse each time.