Rings on fired brass

[JonnyV]

HI i have a ? in the pics you posted i do not see a ring on the un-fired case but the fired ones show the ring now if it was the bullet boxes causing this why is it not seen until you fire the case?

not sure but the ring is exactly where the little plastic partition hits the case when the rounds are in there nose first.

[bpcrshooter62]

ok butt would you not think you would see the ring on the case before it was fired if it was the box that was causing it ? would the ring by chance be where your wad sits on top of the powder? Is there air space between your powder and your bullet ? do you use a plastic wad ? how thick a wad are you using? Do you compress your powder? It could be a lot of things butt with out knowing all the loading info it is hard to tell.
Hope you get it fixed have fun and keep shooting !!!

[JonnyV]

Not sure why. You can't really feel the rings with your fingers either, and there is nothing detectable inside the case. The ring disappears with case cleaning too.

[patchbox]

Any chance that area on the case could be where it’s forced the hardest against the chamber wall at peak pressure? The marks kinda look like reaming tooling marks from a reamer. It’s not making the case deformed in that area - it’s just a surface finish difference after firing so obviously nothing is wrong with the chamber. All the plastic cartridge cases that I have are made of either some type of polyethylene or polypropylene and are pretty soft - I wouldn’t think that soft plastic would mark up the case like that from a road trip to the range but I could be wrong.

[patchbox]

However, you would think those marks would be closer to the chamber mouth as the brass is thinner in that area and probably expands the most.

[JonnyV]

I think what happens is that the round kind of spins in its little silo and the case gets rubbed enough to make those marks. There is nothing in the chamber except a high shine. Since the marks go away in a tumbler, I'm thinking its just a minor superficial thing.

[patchbox]

Yeah - you’ll know soon enough the next time you shoot it - observe the brass before you chamber and after you eject it. That’ll tell you for sure where the marks are coming from.

[bandanaman]

I recently momentarily freaked out at noticing rings similar to these myself. I think I missed noticing them chambering them during a match as there's other things on your mind at the time and the brass is still shiny from cleaning and therefore not as noticeable. While decapping you are paying more attention ,things are a little grubbier and more noticeable. I will try to post a photo of some cartridges loaded in June and did a 2500 mile round trip in my MTM boxes.....four I flipped to use for foulers and you can see the double lines. The lines were less noticeable after only 1000 mile journey to the shoot but were there just the same....much more evident now that they are tarnished .However why the line doesn't show on the unfired case is still a mystery to me..... my first time trying to post aphoto isn't working out so well !!!!