I use wet/dry 320 grit with WD40, pushed into the bore with the end of my thumb, then rotate (twist) the wrist, back and forth, turning the barrel every 15 seconds or so.
I put a patch down an I inch to collect "dirt" then pull that out after I'm finished with the crown.
This leaves, for me, a perfectly polished, smooth crown without any coning. I personally do not believe in coming a bore. Each to his own.
Smoothing the crown to allow thicker patching will allow tighter loads, that do mot fail with heavier loads.
My Bill Large .58 barrel gave me the best accuracy at 100 yards with 140gr. GOEX. That was in the later 1970's. Groups ran an inch to 2" at 100yards, shot dirty, one group after another without ever a thought about wiping the bore. My combination then was a .022" denim patch and .575" pure lead ball and 140gr. 2F.
My other 2 .58's, a Numrich UH and a Zouave, both shot best with the same patch and ball, but with 120gr. of the 1970's GOEX, as well as 130gr. of the Meteor (Scotish) 2F. These rifle's muzzles were "finished" in the same manner. Those two rifles were capable of making 2" 100yard groups. None of these rifles would shoot tighter than about 6" at 100yards with 100gr. or less powder. Maybe it was the powder of the day, or a combination of factors. I was an accuracy nut in those days. Might have similar feelings today, even if I now lack the precision.
Crowning, with emery or wet/dry. For muzzles that are fresh-cut, I use one of the grinding stones that has a 1/4" shank for an electric drill to "cut" the initial 45degree angle, then use the thumb and wet/dry paper or emery cloth. The paper does just as good a job as the cloth. What the smoothed muzzle does, is allow with pressure or a smack with the starter knob, the cloth and patch to conform, fit into the muzzle without tearing or hurting the integrity of the patch. It also allows a thick enough patch to seal ALL the powder gasses behind the ball and deliver ALL the accuracy a particular load is capable of. To prove that the tighter the load, the more accurate, one need only observe what the bench-rest shooters are using. They go to what I would call the extreme of using oversized balls AND thick patches. In my Goodoien .40 barrel (.38 bore dia) I tested this using a .400" ball and a .0235" thick mattress ticking patch. The accuracy was not much better or any at 50yards, yet was easy to load. I also tested .320" balls in a .32" bored rifle with .0215" patching. They also were easy loading. This simply shows that with this crown, the smaller calibres are easier loading as there is less lead to move. Loading .690" balls in my .69 rifle with .021" denim patches, is a chore. You have to really want that patch and ball to conform into the bore. They will, but it takes a good smack of the palm on the starter's knob.
These are "before and after pictures" of a muzzle belonging to one of our members here.
