Sorry, I thought we were talking about a simple muzzle-loading pistol, not a revolver. Most of us tend to call BP revolvers 'loose-loaders' since they don't actually load via the muzzle.
Conical are just fine in most revolvers - where you can actually get one in between the chamber and the frame, that is. The products of this mould - at .452" - just may be too small. The idea is to throw a projectile that will actually shave a little lead ring on being forced into the chamber, this ensuring a good seal. Anything less than that will result in the recoil thrusting the ball/bullet forward and jamming the action.
tac