I got some 2nd hand 6.5 Grendel brass on here and noticed a very consistent line/dent right at the shoulder of the case. At first I thought some cases were hitting gravel but it appears on 80% of the brass in the same location. Any ideas on what would have caused this and is it anything to worry about?

Grendel brass

It’s a piece of brass off your cleaning brush .

Did the brass come out of a semi auto ??

Yeah looks like it came from a semi auto. Typical brass deflector dents half way down the case body. This brass hasn’t been resized yet. Only ran it in my walnut shell tumbler for 4 hours.

I'll bet they're just ejection dents. I wouldn't worry about them.

+1 Bristle off bore brush. Been there done that


Lefty

Little piece of something stuck to the chamber.
Had a piece of seed coat do something similar.

A guy on another forum said that it could be a sharp feed ramp on an ar15 barrel causing it. Some Cases have dents half way up the case.

Thanks for the opinions.

A had 300 blackout that was scratching cases. There was a burr on one of the locking lug recesses of the barrel extension.

Actually, I had a Faxon barrel in 6.5 Grendel that made marks on brass in a similar manner. I sent it back and they supposedly polished the chamber and it did seem to be much better but it was never quite perfect. I was told there were "artifacts" in the chamber from the nitriding process. At any rate, it's nothing to worry about IMO.

Good luck.
Seems a good look at your chamber is a good first step (lotsa light)
If nothing obvious many separate the upper and try approximating a feed from the left stack and the right.
Also might try ejecting unmarred brass.

Happy New year!

Th good news is this isn’t brass from any of my rifles so I won’t need to check. It was from another member on here. I was just worried about reloading and shooting it with those marks.

+2 for bristle off cleaning brush