I have some 1850s-1906 BP rifles that have what looks like dirt and oxidation of some kind stuck in the barrels. I would like to clean them out as best as I can to help preserve them better. What would you guys recommend?
This isn't rust. It looks like there was something poured or sprayed into them before storage and it turned a tan color with a dirt/mud consistency.
I was thinking about a brass cleaning brush on a shotgun cleaning rod chucked into a drill.