When I shot a TC 48" twisted rifle - 40 years ago - I found I could not load a tight enough combination that would shoot well (patches cut on loading, then mostly burnt marks when fired) until I re-crowned the muzzle.
I did that by smoothing the tool cut angled corners.- rounding them. After 'fixing' the sharp crown, and with further testing I found a .495" PURE lead ball and 'brushed' denim patch worked best - spit for lube for target and bear grease for a hunting lube. The 'brushed' denim I measured at .022". Since I do not have that very same material today, I cannot tell you what it measures with today's methods - suffice to say - it sure as heck wasn't .015". That barrel, with my young eyes and NEW homemade GOOD sights, thick patches, .495" pure lead balls off a bench, would put 5 into an inch and one half on centres at 50yards - no wiping needed. seems to me, it took 80gr. to 100gr. of the GOX or GOEX as well as Curtis and Harvey 2Fpowder to shoot well. It did NOT like 3F of any make, it seemed.
After I pulled that button rifled TC barrel off and installed a Bauska .50 barrel, cut rifled and also 48" twist I'm sure, I was able to shoot 1" and tighter groups, 5 into a single ob-long ball hole with the same ball/patch/load combinations. Even then, guys at the NMLRA were using different loads for different ranges and doing a LOT of wiping. I strove to match what their "Buffalo" cross stick contests were producing for accuracy and pretty much succeeded doing that, but not shooting off cross sticks - only from a bench.
Ned Robert's book noted that if the rifle is properly loaded, one should be able to shoot all day without having to wipe the bore - the next one loaded, cleans the last one shot idea - we learned what we had to do, as to ball and patch combinations, to do exactly that.
