I would wrap steel wool around a brass brush chuck it in a drill and go after the chamber. Hard to do any damage with steel wool. The Rossi's I have shot were surprisingly accurate almost to the point of embarrassing my custom rifles. Please post up your loads as I am about to get started on load work for my 6AI as soon as the damn PTG magazine gets here. I didn't want to work up loads with the factory OAL and then do it again with the 3.1" mag.

"When you disarm the people, you commence to offend them and show that you distrust them either through cowardice or lack of confidence, and both of these opinions generate hatred." Niccolo Machiavelli