Using a strip of .020" compressed patch thickness, lubed with WWWF and a .508" ball, we easily loaded Taylor's Virginia .50 with the deep, .016" rounded rifling. He has a nicely radius shaped and smoothed crown, not a cone, as the crown is virtually 1/8" deep - but it as no corners and is smooth. With the strip of cloth, we were then able to simply pull out the ball and check the patch - no cuts, no tears - perfect with the ball nicely engraved with cloth stick markings all the way around, just as Lyman professed back in the 70's in their book, Black Powder Handbook. Seems a lot of guys who have that book or have read it, missed the part where the ball needs to be impressed by the cloth ALL the way around which means the bottom of the grooves as well.
In my .40 barrel, I load a .400" ball with from .019" to .0235" (compressed measures) ticking and denim without trouble, and without tearing the patch. The bore is .398"- .002" smaller than the ball itself. This barrel has .010" deep rifling.
My .69 uses a .682" ball with a .030" (compressed in calipers, .025" compressed in a mic) in it's .690" bore with .012" rifling depth.
Due to what I have noted above, many of us up here who used similar loads, have a great deal of difficulty understanding why some guys have difficulty loading much looser combinations, balls .005 to .010" smaller than the bore and a thin .015" patch.
Perhaps all of these 'trouble' rifles have extremely rough pitted bores from shooting Pyrodex or other chlorate or perchlorate powders - or possibly from poor cleaning practices? Something is different - much different. It is not a matter of strength - our women also use the same combinations we use, albeit slightly looser - .005" under sized balls with wet (not just damp or merely licked) .020" to .022" patches.
Might be the crown's shape?