Maybe, but there'd be the issue of the sabot transiting from chamber to barrel, through the forcing cone, without having it tear or blow out of the cylinder gap slightly. That's why we don't use a patched ball in a revolver (they're sort of an early form of sabot). Wonderwads make it through OK, but that's a little bit different-- by the time the wad hits the gap, the ball is already in the rifling. Then again, if you want to shoot smaller balls, go with a Navy or Police revolver. If it's more velocity you want, there is the Colt Walker or the Dragoons, just waiting for you. Then there are the BP single shot pistols, which you can load with sabots if you have a good reason.