Strange line on 303 British Case?

[Chubbs]

Hello

Does anyone know what this strange line is that has appeared on my 303 British case.

Attachment 84420
PPU case bought new and loaded without any alterations. Line has now appeared and goes all around the case. Could the chamber be causing this.

regards Chubbs

Information

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[Peter Laidler]

On all of the cases or just this one? Been reloaded? Too many questions for an answer

[Chubbs]

Hi Peter

Yes on every case (over 90). Only noticed when reloading for the second time. So only fired once.
Cases from original batch which have been loaded and not been fired do not have the line.
Cases have only been neck sized after first firing.
I have tried neck sizing other cases and the line does not appear.

Regards Chubbs

[Aragorn243]

I would fire one without the mark and look at it to see if it is occurring in the chamber to narrow down the possibilities.

[Chubbs]

Hi Aragorn

I am going to do this, but just wondered if anyone had had marks like this before and if it is the chamber, will it be ok.

Regards Chubbs

[Aragorn243]

Wild guess if it's from the chamber and perfectly round it's probably a minor milling defect in the chamber which you might be able to polish out. But I'll sit back and listen to what the experts say. There could be more serious issues and they would be the ones to best advise you.

[browningautorifle]

The reamer could have had a nick in one flute, when cutting the chamber this would happen. To remove it, though it doesn't matter, you can use a mandrell in a drill with fine machine paper and oil. Run it into the chamber and the line will disappear with polish. Remember, the line doesn't matter. It's not hurting your brass.

[Chubbs]

Hi Guys

Thanks for the advice. When I run my fingernail down it , it snags. Should really say its more a scratch but very light. Was thinking that it may make the case prone to separation like scoring glass. I know brass is not as brittle as glass but its under a lot of pressure. i am probably showing my ignorance but I apologise for that. Just rather be safe than sorry.

Regards Chubbs

[browningautorifle]

Was thinking that it may make the case prone to separation like scoring glass.

Maybe, but I wouldn't worry about it. Specially if you're neck sizing and use that brass in that rifle.

[Aussie48]

A stab in the dark from an old reloader, it looks exactly like helping the chamfer tool especially LEE being placed on at an angle instead of square

Dick