+1 to it being a pitted bore, but also that the bore is fine for shooting. I wouldn't even worry too much about it making the gun harder to clean as long as you're using modern, non-corrosive ammo. If you've got to get primer salts out of the pits yeah that's a pain in the butt, but with modern commercial and my own hand loads I don't worry about it at all. At the end of the day it doesn't hurt the gun to have a bit of soot hiding in the barrel as long as it's not promoting rust.