From a Dixie Gun Works Catalog.
"Black streaks and charred holes where patch lay in grooves. Caused by the patch too thin. Gas blowing by. Use a thicker patch or larger ball diameter.
Frayed holes worn through where patch contacted lands. Caused by rough or rusted lands tearing the cloth. Try stronger patch material or freshout or recut the bore.
Slits in cloth along contact of patch and land corners. Lands are too sharp, patch is cutting while loading. Scrub bore with steel wool or lap, try stronger or thinner cloth
Annualar (I don't know, look it up) slit cut part way round where the ball lay, some soiling from powder fouling. Muzzle too sharp, cuts patch when ball is started into bore. Chamber muzzle or try stronger cloth.
Black circle in center where ball lay, some soiling from powder fouling, minimum of burnt streaks at groove marks, cloth everywhere intact. Good lubrication, bore good, patch can't wear or be worn through. No cure needed, rifle should shoot accurately with correct powder charge."
The Doc is out now.