I doubt you have a bore issue. especially with a Pedersoli. They make quality stuff. Only a couple of times in 40+ years with muzzleloaders did I ever see a bore issue on a new gun and they were usually junk to begin with. I think your problem will be cured by a wet patch lube as stated previously.
Don't mess with any abrasive material around the muzzle or crown, you could cause damage.
Don't mess with any abrasive material around the muzzle or crown, you could cause damage.