Sir, the barrel is a smooth bore and had some rust in it. I bought the gun to play with and do not have much invested in it. We shoot carpenter bees around some of my buildings. A load of powder with some wad over it then some course builders sand at close range destroys them. It will not put holes in roofs or walls from several feet away. It also cleaned the rust out of the barrel. I wouldn't use sand or anything else abrasive in a good barrel. I had built a couple percussion guns from old parts and take off barrels. Had bored them out as smooth bores and used sand, shot, ball and bullets in them. To me the black powder guns are fun. I have some nice ones I take really good care of.Others we can play with and enjoy. We are old enough now that sitting under a shed, drinking coffee or tea is good. Having a flintlock handgun loaded with sand for bees is better. Shooting or shooting at a chipmunk with a black powder rifle is fun. Unlike shooting a deer there is no work after the shot. Some other critter will come along and eat it. It is a shame some of us didn't learn to relax and really enjoy life when we were young. To the members of this forum, Thanks, y'all have taught this old dog much and I still have a lot to learn about the black powder guns.