Bright ring on brass ?

[Elroy]

I bought a new Mossberg Patriot Bantam compact 7mm08 a few months ago,and just now getting around to fiddling with it,and I notice that brass fired in it all have a faint bright ring a little over halfway up ,a little closer to the shoulder than the head. I looks like the start of separation,but it's too far up. the ring is in the exact same place on them all. I don't feel anything odd,or stiff on ejection,and the rifle shoots very nicely. It does seem to surprise me on velocity though. I seem to get very close to the speeds in printed data,and I have a 20" barrel..Could this just be the way the chamber is machined,and nothing to worry about. What are your opinions?263117

[beshears]

Straighten out a paper clip and bend one end at 90 degrees that will enter case mouth. If it is a case separation ring you should be able to feel it inside case. Factory shells or formed 308 or factory 7mm08 cases?

[EDG]

That looks like a faint reamer mark in your chamber that is being picked up by your cases. You can check your fired brass or just check your chamber to see if headspace is in spec.
If your headspace is ok I would ignore it.

[Elroy]

The ones pictured are R.P. that I bought as once fired,and I shot them once before I loaded them for the rifle in question,so this would be the third firing. I can't feel any thing in the inner case.

[Elroy]

Thanks EDG,and beshears.

[toallmy]

If it's not just because they vibrated around in a plastic ammo box , the paper clip as mentioned above should tell you something .

[Win94ae]

My Howa does that to my cases also. I don't see it as a problem, just an anomaly with the chamber.

[Elroy]

If it's not just because they vibrated around in a plastic ammo box , the paper clip as mentioned above should tell you something .

No, it's not from the box,and I don't feel anything inside the case. I think it is probably just an anomaly in my chamber as others have said. I appreciate everyone's help.

[Bazoo]

I'd run a scotchbrite pad inside the chamber to see if I could even it out.

[ioon44]

I have seen .223 brass start to separate in that area.

[1006]

If it shoots well, then ...... You will always know which brass is yours.

[sureYnot]

You s sure that isn't from the bell of your hand held deburring tool? I threw away quite a few .223s with a mark like that until I realized where they came from.

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[Elroy]

You s sure that isn't from the bell of your hand held deburring tool? I threw away quite a few .223s with a mark like that until I realized where they came from.

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Yes,I had one of those Lee thimble type chamber/ de burr tool years ago,and it would scratch a ring on the brass,but these only get the ring after firing. I may split one tommorow just to get a look at the inside,but I would be surprised to find anything .

[shooterg]

Had an M1A barrel left similar marks on .308 brass . Was from the chamber reamer . My bad, but shot fine.

[M-Tecs]

Way too consistent and even to be head separation ring plus it's in the wrong location for that. They use a barrel nut so it easy to remove the barrel to polish it or Mosseberg should fix it. https://www.mossberg.com/service/

[Elroy]

I went ahead and split one just to take a visual,and it looks good,so I'm not going to worry about it. I guess I could send it in for fixing,but it was cheap,and as long as it functions,and doesn't kill brass prematurely I'm happy.263136

[nicholst55]

IMHO that mark is from a ringed chamber, caused by a metal chip that was caught in the chamber reamer. A good gunsmith would have either polished that out, rejected the barrel, or cut it off and rechambered it. The factory may or may not replace the barrel.