Sounds like it was shot a lot "back in the day" with corrosively primed ammo, and not cleaned properly or at all. Were it me I would seek another barrel too- even if this one stopped keyholing I bet it would still yield shotgun patterns for groups.
Probably. But if he has all the makings to shoot a few shots with a shortened bullet before he heads off into $$ spent on new barrels or rebores, might be worth the time since it only costs a few bullets, powder and primer.
