I have a set of Uberti 1872 Open Top .45's that shoot round balls extremely well. I load 6.1 grains* of Trail boss, then seat the cast ball ALMOST flush with the case mouth (The rules of the game say the projectile can't be seated below the case mouth). I made a seater die that leaves the sprue stem above the case mouth so the projectile is sticking out of the case about .020" or so.
Then for lube, I've got some solid stick grease that gets smeared into the space around the case mouth. It chrono's 850 fps, shoots to point of aim, is extremely accurate, and recoil is nil. I've used balls up to .457" with no real difference in performance, but I normally use .454". If the rounds will chamber in your cylinder without crimping, there doesn't seem to be any need to crimp either - crimping doesn't crimp the ball anyway, as contact with the case is ~.225" below the case mouth.
* 6.1 because that's what the corresponding RCBS Little Dandy rotor just happens to throw. I started with five grains, but ignition was very inconsistent and primers were backing out.