How to Lap a Black Powder Barrel

Brush the bore to remove any debris that may be stuck, and then thoroughly clean the barrel. Attach a cotton ball to the end of your cleaning jag and run it down the barrel. If the cotton ball is torn, you need to lap your barrel. Clean the barrel to remove the cotton ball remnants.

Cradle the rifle against a wall so it is stable and will not easily move or fall.

Coat your lapping bullet with lapping paste. The lapping bullet is a lead slug, so the abrasives push into the bullet and do not scratch the bore, and it should have an 11 or 12 Brinell Hardness Number, which tests the hardness of metals and alloys. The lead slug should be the same size as the bore. Lapping paste is an abrasive paste that breaks down while it smoothes out the bore during the lapping process.

Load your muzzle with the lapping bullet. You may have to shove it somewhat hard to get it to rest against the powder. Push the bullet through the bore using a cleaning rod if necessary.

Wipe down the bore between each stroke, where the bullet is pushed down and then up the barrel, to remove any grit left by the previous stroke. Fire 20 to 25 shots with the lapping bullet coated with paste. Replace the lapping bullet if it is compromised by the lapping paste and ceases to work properly.

Clean the barrel thoroughly with a solvent to remove the lapping paste. Retest the barrel with the cotton ball on the end of the cleaning jag. Repeat the process until the cotton ball comes out without damage.

Wrap your cleaning brush with cotton cloth, soak it in lapping paste and create a bob. Push the bob up and down inside the barrel so it goes in and outside the barrel. Replace the cotton as it disintegrates and add more compound.

Polish the barrel using brake and clutch cleaner and a tight patch. Move the patch through the barrel until it comes out clean. Wash the barrel in hot sudsy water and dry it. Add protector to the inside and outside of the barrel.