A friend of mine has a mas 49/56 in 308. He was having trouble with extraction so we installed a new extractor. It fired 3 rounds OK then the cases started sticking in the chamber again. There is one case stuck in the chamber now with about 1/4 of the rim just about ripped off. He was shooting civilian brass cased ammo.
From looking at the extracted brass, it looks like there might be a rough chamber issue-there are bright rings around the case.

Has anyone experienced thios issue and if so how did you correct it?

From previous topics on the same subject it appears that the cure is to polish the chamber, check some of the similar topics available in archives:

viewtopic.php?f=159&t=85863

viewtopic.php?f=159&t=101257

viewtopic.php?f=159&t=102570

viewtopic.php?f=159&t=66975

viewtopic.php?f=159&t=67492

viewtopic.php?f=159&t=62543

Thanks for the links. It would appear that my assumption of a rough chamber is correct. Now to figure out how to polish it.

To poilsh the chamber you can use a .308 case fitted through the primer hole on a rod and very fine lapping compound.

The closed shape of the receiver prevent a straight access to the bore from the rear without removing the stock (there is a hole lined up with the bore at the back of the receiver but it's blocked from use by the bolt cover latch and the stock has to be taken off the receiver before the latch is removed.

You can either use a very flexible rod from the receiver side or use a long rod with rubber protection through the barrel to carry out the polishing of the chamber.

On a rechambered rifle, you don't want to remove unnecessarily the barrel from the receiver.

kelt

Thanks, I will relay the info to my buddy.