If you are shooting bare lead bullets that rub against the lands and grooves, you have leading.
Use a modern lead solvent- Hoppe's #9, Shooter's Choice, and others all work. Run a solvent soaked patch down the bore. If it comes back out with black or silver lead streaks, you have Leading.
Its pretty hard to see leading visually in a MLing barrel. Not so hard looking through a modern suppository barrel. T/C guns have been notorious on this site for being described as " Shot-out" Because the grooves have filled up with both lead and BP residue when they are not cleaned properly.
Members here make a habit of scouring both sporting goods stores, and pawn shops looking for these guns, or barrels. They buy them cheap, take them home, use lead solvents and bore brushes to clean out the lead and fowling, properly, and then turn around and sell the barrel or gun for a huge profit.
Cleaning your barrel after shooting bare lead balls out of it should routinely involve using a bore brush- I like my bronze brushes--- with a large cleaning patch soaked in lead solvents run down and up the bore. Then let the barrel sit with the coating of solvent in the barrel, so that the solvents can eat UNDER the lead to separate it from the barrel. Give it 15-30 minutes. Then run patches down on a cleaning jag to pull the lead and solvent out.
FEEL the bore as you do this for blockages, and always check it with new cleaning patches. If there is any gray or silver streaks on a clean patch, repeat the process until you get clean( white) patches coming out of the barrel. You want the barrel to be as clean as the first day you cleaned the factory sealant out of the bore, every time you clean the barrel after shooting it. When you are satisfied that the barrel is clean of lead and other fouling, THEN, oil the barrel for storage. What you use to protect the bore from rust depends on how long the gun will be store- and where it will be stored-- until the next time you shoot it. Long term storage requires a product like B/C Shield.
Always remember to flush out any oil or grease used to protect the bore during storage, before you take the gun back out for the next shooting session. Cheap isopropyl alcohol works fine for this purpose. If you don't clean this out, it will foul the barrel the first time you put powder down the barrel and shoot it. Worse, with a T/C, and its powder chamber and small holes leading from the chamber to the percussion nipple, or Th(flinters), it will gunk up these small places and keep the gun from firing. :hatsoff: :hatsoff: