Hey all,I picked up a really clean condition USP 9 full size with match trigger group installed. Also has a new set of Heinie rear and trijicon straight eights. The gun looked in great shape when I examined it. Got it home and noticed a rough mark in the chamber on top. Then I could see it had erosion from gas escaping around chamber around hood. I cleaned up real good and shot it. Groups really nice and tight, but spent brass had dark black stripes on one side corresponding to chamber erosion. Anyone seen this before? Should I be worried?

You say it runs perfect & is quite accurate. So.................. where is the concern?  

Are you positive this is caused by gas erosion & not anything else?

There’s a pitted mark in the chamber that I believe is letting gas escape. Right near the breech face I can see flaming from the barrel. I just don’t want it to mess up the breech face. The chamber gets really gummy after a few mags, but no stoppages so far.

Ok, then send it in for warranty. My shop recently sent in a customer's gun for a glitch in the feed ramp. He had a new bbl installed & back in a couple of weeks, IIRC?

Thanks. I talked to hk and sent pics of chamber. Definitely a defect. Gonna send it in thanks!