Those are burn-throughs or the patches were compromised by a sharp spot at the muzzle crown, then blown through.
You didn't say if the rifling is round-bottomed or not. Nor did you give the patch thickness. Those patches look pretty bad.
To determine the minimum patching to seal, do the math first.
For a .54 bore, we'll use some sample numbers to get you going. Like .012" deep square bottom grooves and a .54" bore.
Bore is .54", + .012 +.012 grooves on each side = .564" to fill with ball and patch.
Ball is say .530". Subtract .564 minus .530 and you get .034" of grooves to fill. Divide by two for each side of the ball, and you get .017" thick patching.
So.....you'd need a minimum of a .018" thick patch for that combo. A thicker patch would seal even better with compressed cloth.
I always shake my head when someone says, "Start with a .010 patch." Really? Knowing nothing else, they just throw numbers out there.
Smooth your muzzle with Daryl's method and that should help with cuts at the muzzle.
I use The Minute-Men patching by Ron Hite. Extremely tightly woven canvas. Cannot see sunlight through it after firing. I get the UNTREATED stuff versus the teflon coated. Worth calling an ordering some. Call in the evening. Leave him a message if he doesn't pick up. He doesn't use the internet or email shown. Just call.
God Bless, Marc
