Thread: Cases being marked after chambering

After going to the range on the weekend I noticed that all my fired brass has a small dent at the exact same location. I gave the chamber a good scrub with a bronze brush and some Hoppes solvent but just chambering an empty case leaves the witness mark (to a lesser extent than a fired one).

Any ideas what it could be? maybe i chambered a round with a bit of grit on it and it has left a permanant mark on the chamber wall? I would have though that the steel would be too hard for that. maybe a bit of carbon buildup?

Any thoughts appreciated... also any suggestions on how to remedy it before sending to a gunsmith.

Cheers.

It's it a bit of an ar? If it's an ar it could be from the case deflector.

it's a bolt action 223. I can get an empty case to mark by hand feeding and chambering it.

Originally Posted by MGNZ

it's a bolt action 223. I can get an empty case to mark by hand feeding and chambering it.

Then it must be something in the chamber, do you have a chamber brush ? Not a bore brush, but one that fits the chamber size? It cant be a "dent' in the chamber as that would leave a bulged spot on the case, your cases show a dent so something is pushing into the case, like you say could be a bit of grit.

Looks like an indentation which means somethings stuck to the chamber wall. Im guessing this hasnt happened from new? My suggestion is its probably a bit of brass searf from a case put the chamber brush back in attached to a cordless drill with a squirt of crc or break free and it should be gone. Similar has happened to me and i put it down to little copper slivers that sometimes get shaved off flat base bullets when you are reloading a bit to fast.

Thanks Guys. I will source a chamber brush and give it some more heavy duty persuasion. I got the rifle second hand so couldn't say if it's a manufacturing defect or not, but it's done it since I've had it. If the chamber brush doesn't work I'll send to to a gunsmith for reaming (assuming it is a manufacturing defect in that case). Cheers.

Funny last night I was watching this:



It may help if you can get your hands on some Cerrosafe Alloy

Initially go KISS.
If is happens when not firing as well that is good.
Mark the base in one spot with a felt tipped marker or just use the first letter of the case makers name.
Insert case with mark/first letter at 12 o'clock.
Extract and orientate in the chamber area where the mark appear wrt to your witness mark.
Take to from there. You may see something with a good torch.
Look in the locking lugs area (a bit harder to do) as well for anything that might be marking the case as the extractor claw drags it out and it springs the case to that side. Would need quite a bit of force to dent the case though.
Check if the mark orientates with a locking lug.
Does your rifle have 2 or 3 locking lugs?
The mark has quite sharp detail at the bottom of the dent like something sharp and pointy has caused it.
Are you having any difficulty chambering a round?

You get the drift at any rate.

I see another lighter dent about the case diameter further back. Scope mount screws protruding and being connected at some stage?

If it was something in your chamber there would be marking from the shoulder down to where the dent is. When you draw the bolt back does the case pop up as it exits the chamber? Many rifles dent the neck mouth as the ejector slaps it against the action on extraction

Thanks for all the advice. Think I have got to the bottom of it thanks to you lot.

If I chamber a case and very carefully draw the bolt back and catch the case with my finger before the ejector slams it against the receiver then they don't dent. the more aggressively I open the bolt the sharper the dent is.

the ejector is bottom left on the bolt face and the ding is top right, the machining inside the receiver is pretty sharp on the corner where the bolt lugs are cut into the receiver so that is the issue.

Dang, seems like it's going to be tricky to sort out, all my nice reload brass is getting dinged after each fire.

Wonder if I could reduce the ejector spring force? or just ignore the dings and keep reloading them...

Looks like good progress.
I had a second hand rifle which had bad galling on the locking lugs thru the previous owner never lubricating them. I could see a jagged edges coming off the locking lugs it was that bad. The lugs on the bolt were reasonable though. Not saying yours will be like that but would be worth checking. There is a distinct sharp point doing your damage. You need someone with a borescope to have a good look now to further isolate the cause. Aside from the difficulty I wouldn't consider messing with the ejector spring tension.

I also had another rifle that would slightly dent the end of the neck on extraction/ejection - wasn't an issue just a cosmetic annoyance.

Anybody know where I can get Cerrosafe from?