Hello all, I am a first time Mosin owner as of recent. I purchased a 91/30 through J&g Sales. A 1930 Tula. It was just packed in cosmoline, and the finish was horrible. I cleaned it up and noticed this while considering a method to clean up the bore. (Check the attachment). What would cause the silver band? Does this look counter bored? Any ideas on how to clean up the bore ?