I hate to bring this up, but some repeated agressive pushing of heavily oiled sanding cloth (what is the proper name?) with a dowel or cleaning rod, through the barrel will remove a lot of what looks like pitting. Just don't let the abraisive contact the breech of the gun and ejectors, which will round off the square edges.

Bill, are you refering to emery cloth?

Cheers
Marcus

Emory paper comes in many grits (no Charley, not the eatin kind) be very carfull with at. You might want to try crocus cloth. It's very fine.

I would'nt live long enough to make any head way on this barrel useing crocus cloth.

This was discussed on an earlier thread and someone recommended a copper cleaning brush wrapped with a cleaning cloth, covered in Hoppes and then a drill on the rod to work the bores.