I'll give you some tips. DON'T "polish" the bore of a Knight rifle with ANY KIND of an abrasive compound. That's a good way to ruin it! To break it in, just shoot it with the proper powder charges and projectiles, and clean it correctly after shooting.

BORE BUTTER is essntially crisco with a yellow coloring added. Forget it!

Clean powder fouling residue out of a ML with 2 quarts of boiling water poured through the bore after you take out the breechplug. Use something like Shooter's Choice to remove any buildup of plastic from sabots or the wads on a Powerbelt bullet, if you see any after drying the bore. Then prevent rust in the clean bore after cleaning by the use of Birchwood-Casey Sheath.

Shooting and cleaning will break in a barrel, and not damage it in the process!