Hi, Blooch,
How rough? Are cases sticking or won't feed? Sometimes a little fine emery paper (600 grit is a starting place) in a slit dowel rod will do the trick. But you have to be very careful you don't get the front of the chamber bigger than the rear because then the cases won't extract.
Clean the chamber well, and examine it carefully. If it has a marks from a little surface rust, try the above. If it is really bad, the only answer may be a new barrel.
Jim
