I still contend that to obtain the best accuracy from guns that must be loaded without a false muzzle, what I call the radiused crown is best. Tight ball and patch combinations
give better accuracy than do loose ones. Loose combinations only, can be loaded without the use of a short starter, whether in crowned or coned muzzles. The muzzle shape, what I call
the radiused crown, is very close to what is used in metal drawing dies used for making bullets and ctg. cases. In our rifles, it is a short, smoothly radiused portion at the end of the muzzle, & needs only be 1/8" deep.
A long taper, as in a "cone" shape, creates a longer bearing surface to the ball and patch combinations thus it creates even greater friction & harder loading with the same tight combinations
which load quite easily in a simply radiused crown, with the use of a short starter.
An example of this was a few years back, our late friend Leatherbelly asked me for .40 cal balls as he was out and didn't want to attempt casting them in the winter time. At that time, he was
shooting a coned Tenn. rifle. The balls I was using in my own .40, were .400"x.400" from a Lyman mould. He complained that he could hardly get them loaded, even with his .018" denim patches.
The next day we shot, I not only noticed his trouble, but loaded his rifle myself - @!*% hard it was to get them started, but of course, once put down the bore 6", then went down easily. Getting them started was very difficult, while loading my own rifle with 10oz denim at .0225", was not difficult at all. One smack with my hand on the starter and in they went. His took a few smacks even
though it was a looser combination, by just over .004".
I tried coning in my .45 GM barrel prior to this and found a loss in accuracy, so cut off the end of the barrel and re-crowned it. That cone, was only about 3/4" long, but, it more than doubled my group sizes at 50yds to 1 1/2" from the normal 1/2" to 3/4".