I recently went to the range with my P220, in .45 ACP. It has been a long time since I used it. It has around 3000rds through it. Everything internal is original.

I picked up all my brass this time, which is something I have rarely done that in the past. Every piece of my brass has a perpendicular dent in it, half way up the casing. I'm not exactly sure how to post an image from my phone. Tool seems to only want a web address for the image.

My best guess is the casing is getting a dent during extraction, as it is pulled back across the next round. But I have no idea. I'm not a gunsmith. I don't know where to start.

My friend suggested it may be the Mainspring, but recommended posting here for the collective forum to ponder.

Thanks for your time. My apologies if this is a previous thread. I don't even know what search terms to use to figure that out.

One thing you may be able to try is record the pistol firing using slo-mo on your phone.

The casing may spin while being ejected, striking the ejection port on the slide.

Other than that, I have no idea.

Were it mine I would re-spring .I always bought Wilson or McCormick assortments ,I am a tinker ,can't just leave things alone.

More than likely, it is the case striking the edge of the ejection port. Many pistols do this to some extent.

quote:

My friend suggested it may be the Mainspring,

Recoil spring maybe. Mainspring-no way.

I have seen this on 1911.

Shoot one then unload.
Is the chambered unfired round dented?
There is a 1911 maladjustment that will do that but it shouldn't happen on a P220.

Most likely the empties are hitting the edge of the ejection port. Might be the recoil spring or the extractor.

I have both a 1998 P220 and a 2019 P220 ASE. No dents on ejected brass for me either. The old 220 was sent to Sig for the SSP and got a new recoil spring. The newer gun has not reached the point where the recoil spring needs to be replaced. I would get a new recoil spring.

Thank you!

I will try the test recommended, and then a new recoil spring.

Thank you for the help.