A building buddy of mine was pushing out a barrel when the bolt slipped through what ever he was using to protect the barrel. It peened the edge into the chamber mouth. I tried to drop a round in but the "swell" kept it from seating properly. It needs to go in about another 1/8"

How would be the best way to remove the "burr" as we will call it. I was thinking chamber reamer but this is a chrome lined barrel. I'm amazed it dented the way it did. It didn't seem to get that hard of a hit.

I did this on a Yugo underfolder.  Was using a 3/8 extension which went through my pennies and iinto the chamber. Ended up doing surgery. Filled in the low spots with my mig and used my dremel to hit the high spots. Took the better part of the day to get it right. Rounds fit perfect now and the rifle shoots like a champ.

Yep - - - Dremel Time  ! !

But remember - - - it's a lot easier to remove metal than to add it  ! ! !