Barrel lapping?

[Schutzen]

Before I lapped the barrel, I would try a very thourgh "deep" cleaning. I know this sounds funny, but it's cheap to try. Plug the nipple hole with a metal or rubber plug, then fill the barrel with penatrating oil and let it stand up right for 2-3 days. Then clean the barrel as normal. You will be surprised what will come out. I have done two muzzleloaders this way and restored both to accuracy. Good luck!