Gunsmithing Distinct ring around fired case neck.

[Notdylan]

Should I worry about this? Gun was shooting iffy groups but I think my scope rings were not locked down properly. I contacted the builder and they said:

"Hello Dylan, Appears to be an artifact of machining or possible damage from cleaning. If you wanted to send the rifle in, we can probably get that polished out without any issues. That said, it doesnt look significant enough to cause any malfunction, so I'd just keep going ahead."

I know it's not from cleaning.

 

[Yoteslayer50]

Doesn’t look bad enough to cause problems probably caused by a nick in the reamer or a shaving stuck to it can you feel it stick out with a pointed object or is it like a scratch maybe check the chamber with a light to see if a peace of brass or something imbedded in the chamber that could be scratching the brass good luck

 

[Deleted member 10043]

Is it on every fired case?

 

[Notdylan]

Is it on every fired case?

Yes it is.

 

[Subwrx300]

Looks pretty uniform to be a cleaning or debris issue... Is there ring indented on brass, a raised section, or two sections with different diameters? From the photo, it looks like the forward half of neck is slightly smaller diameter than back half. Is this true?

PS side note: what material/surface is the case resting on in the photo? Curious as lot appears raised in alternate sections, to push debris into the channels.

 

[Wannashootit]

That's what it looks like to me as well- as though it's been "necked down" more at the top as if it were forced into a too-tight die or chamber. I'd mike it to see if there's a difference.
Reloaded brass, or factory? Easy to chamber?- no unusual resistance on closing the bolt?

 

[Xander3Zero]

So if you put a loaded, unfired, factory round into the chamber, and then just eject it without firing, it comes out with this mark at the neck? Or do you have to fire the round for it to come out like this?

If this mark is present on all the brass that comes out of the chamber, and the ring is all the way around, I would definitely just send it back to the smith and have them take a look at it and try to polish it out. Even if it didn't affect function, there's just no way I'd be able to get over it.

 

[Subwrx300]

So if you put a loaded, unfired, factory round into the chamber, and then just eject it without firing, it comes out with this mark at the neck? Or do you have to fire the round for it to come out like this?

If this mark is present on all the brass that comes out of the chamber, and the ring is all the way around, I would definitely just send it back to the smith and have them take a look at it and try to polish it out. Even if it didn't affect function, there's just no way I'd be able to get over it.

Not to mention the issues with carbon/soot buildup changing neck tension at that spot over time. Personally, I'd have the Smith look at it and insist on getting chamber recut/set forward if possible. Hopefully they check reamer while they are at it.

 

[Supersubes]

That looks really minor to me. There is a similar ring on your shoulder just above the body junction. I agree with your smith, not gonna cause any issues.

 

[BillyGoatMachine]

Nothing to worry about.

 

[Deleted member 10043]

Yes, I notice rings all the time. By the time I retire brass it has all sorts of rings around them.

 

[Rthur]

As stated above will be fine.
Could have been a minor chip drag in the neck portion or even a burr on the reamer.

R

 

[Yondering]

I've seen that before, could be a few things, all of them minor - either a chip caught under the reamer, or the reamer may have even been ground that way accidentally for example. Either way, it's very minor and nothing to worry about. It would be pretty simple for your gunsmith to polish it out if it bothers you though.

By any chance is this a barrel that was set back and re-chambered? If the original neck was slightly larger so the new reamer didn't completely clean it up, you'd have a mark like that. My first centerfire rifle was a 35 Whelen that I had set back and rechambered to 35 Whelen AI; it has a ring just like that but closer to the case mouth 'cause it was only set back 1 turn. It's still that way all these years later and still shoots great, nothing to worry about at all.