Secondhand barrel, marks on brass = bad chamber?

[phillips321]

Hi guys,

Secondhand R93 barrel here, picked up a few days ago. 300win mag

Firing factory ammo (145grain PPU) I'm getting marks on the shoulder of the brass in a few places. Is this going to be a long term problem? I've left wipe out in over night and given the chamber a scrub with a .410 mop but it's not improved. I've been offered a refund but finding these barrels isn't too easy for an older rifle so would like to sort the problem if possible.

 

FYI these marks are not on the unfired cases.

[phillips321]

And just to confirm this isn't occasional, it's every shot of the 6 so far that have been through the barrel.

[Chris-NZ]

Well there's obviously a blemish in the shoulder region of the chamber but those necks look alight. While annoying, the barrel is still useable and it's highly likely accuracy won't be affected. I'm assuming the bore is OK.

[VarmLR]

Could be that the shoulder area within the chamber simply hasn't been cleaned properly and you have a build up of crud or perhaps some corrosion present. If not already done, can you have it bore-scoped to see? I would with any used barrel, preferably before buying one!  You can buy modest little cameras these days that attach to your phone.  Whilst not great, they should be good enough to check the chamber for anything obvious.  Give the chamber a thorough clean if not already done and see what it's like after.

[Iantohorse]

I don't know anything about R93's, But years ago I had a BRNO that used to eject empty cases with quite a Flip, which used to dent the case mouth and some times the shoulder.  Can a R93 do anything like that ?