Marks on fired brass I bought

[PA_Probe]

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

[JCSC]

Likely from the shell deflector on a gas gun. Usually dents are nothing to worry about, unless they are creased or gouged. If you are concerned, you may put up a picture for discussion.

[VASCAR2]

The gouge or scratch on the shoulder junction to the neck is very common. I think it is from the sharp barrel extension opening for the lugs of the bolt or the sharp edge of the mag feed lip. As the rifle wear in the gouge/scratch tend to diminish. The brass looks normal to me.

[PA_Probe]

Ah that makes sense now. I could see the sharp edge of the feed ramps on an AR15 making those marks.

[Dinny]

The gouge or scratch on the shoulder junction to the neck is very common. I think it is from the sharp barrel extension opening for the lugs of the bolt or the sharp edge of the mag feed lip. As the rifle wear in the gouge/scratch tend to diminish. The brass looks normal to me.

Exactly!

[StoneHendge]

Is there only one mark on each piece?

[PA_Probe]

One sometimes 2. One more pronounced than the other when there are 2.

[StoneHendge]

One sometimes 2. One more pronounced than the other when there are 2.

Then Vascar's explanation seems likely. I have seen marks like that on the shoulder body junction that are caused by brass fatigue, but they appear in several places and in different sizes. After asking, I also recalled a 300 BO barrel I bought a number of years ago that did the same thing, but with 2 marks. They said that it was normal, but offered me my money back which I took and used to buy another barrel.

[Rosecrans1]

I f you want to see really beat up brass, run anything through an over-gassed mini14 or 30. Until I turned down the stock AGV on my PSA Grendel, all my brass was dented. Some in multiple locations. As stated, unless they are really severe, all my brass for the Grendel sized and performed flawlessly.

[Happy2Shoot]

dremal the 4 corners of your feed ramp

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With a fine rubber cone

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Never a stone or sandpaper

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Then polish with a felt cone and Flitz

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Plug up the chamber before you start, and clean up all the grit when you are done.

[Oso Polaris]

I think that is the lugs. Sharp feed lips (metal mags) usually leave a line or pair of line along a good portion of the case body and look like shallow slices/ deep linear scratches.

[Texcl2]