Many, Many of the old guns with pitted bores did not get that way from shooting with BP. They were pitted from shooting early smokeless loads with corrosive powders, while under the false impression through cleaning was un-necessary due to the lack of residue. The corrosive primers had not been a problem when BP was used as the water for cleaning dissolved the primer salts.

Miller/TN
I Didn't Say Everything I Said, Yogi Berra