Get some cast bullets. Take the bullet lube out of the lube grooves of the bullets. Replace it with fine lapping compound. Load them at very low velocity. Shoot about a dozen through the rifle.
Finish up with a bronze bore brush wrapped with 0000 steel wool on a bore cleaning rod, squirt some light oil on it. Work it out good with it.
Give everything a good cleaning afterwards.
It won't remove the pits. But it will smooth them out so that they don't abrade the bullets as much and catch so much copper.
