You guys are correct - I was referring to 'today's barrels - GM, Rice, both square and round, Getz round, Goodioen which has square-appearing grooves - with quite narrow lands. In that one, I use a .398X.397" pure lead RB with .0225" patch - no starter needed (but I use one, or a .400" X .400" RB with .020" patch - no starter needed, but I use one - it's simply a very simple, fast, & easy way to start a snug combination perfectly centred in a bore that isn't coned.
The 'shape' of the crown allows the ball and patch to form together to enter with little trouble. If you search Corbin's (swage and drawing dies for making bullets, etc) site, you might find what I'm referring to. There is an angle that allows easier movement of material, with less pressure required. It isn't a long even tapered cone as many might think as that is not good as it increases friction due to length of engagement, but a more radiused, short angle, which allows this material movement with less pressure. The slipperier the lube, the easier the movement. The shape is easily accomplished on one's machine (angle) cut muzzle, merely using the end of your thumb and emery or wet/dry paper. A lathe can speed up this operation, from 10 to 30 minutes down to mere seconds, depending on what you start with in shape.
As Taylor noted here some time ago, I once re-crowned a fellows TC .50. He couldn't start let alone load the combination I gave him - no wonder, his muzzle still had the machine cut crown as when purchased, except it was sharper than any I'd see till then, without much angle at all. I re-cut the angle with my pocket knife, then with a strip of 'used' 320emery from my bag, 'ground' him a new crown. After that, he could load quite easily and achieved much improved accuracy. No wiping, no loss in accuracy - of 1" at 50 yards - 48" twist, .004" rifling and all.
