Back when I was shooting a VERY deeply grooved .45, with .028" deep rifling, a fellow showed up with his TC Hawkens and complained the ball and patch combination
I had suggested was too tight for him to load. I had suggested a .490" ball and .020" denim patching, if he couldn't load the .495" ball and same patch, although the
larger ball would give better accuracy. That was my experience.
I asked him what combination he couldn't load. .490 and .020" denim. He game me a patch and ball, then I loaded it into my .45 barrel, and shot it on the gong at 100yards - clang.
Standard radiused crown. Yes- it took a smack to get it in, but it went in and down the tube - 3/8" hickory rod.
My bore was .504", groove to groove, almost as large as his .50, but not quite. Mine also had tall lands to impress into the ball with the patch as well.
Tight combinations do not need coning, in fact, tight ball and patch combinations load easier in the radiused crown than in a long cone. The longer the cone, the longer the actual
friction surface, the greater the total friction.
Metal moving dies have short, rounded radius surfaces. Loading oversized balls or projectiles requires moving metal to conform to the grooves. The patch seals while supplying the
necessary lubricant to soften the fouling going down as well as when the 'load' is discharged. ihmo