As Phil said, there really isn't any difference between a ball made for rifles and for revolvers except for the size.
The caliber of a muzzle loading gun is defined by the bore size so a rifle or a single shot pistol which shoots a patched ball will use a ball that is smaller than the bore. Typically, a .45 caliber rifle will use a .440 diameter ball with a .015 thick patch.
A cap and ball revolver does not use a patch on the ball so the ball needs to be larger than the bore so it can engage the rifling grooves in the barrel. Because of this, the chambers in the cylinder are larger than the bore size.
In order to seal the chambers tightly and to keep the balls from moving forward when the gun recoils, the ball, before loading must be larger than the chamber diameter. That's why the ball for a .36 caliber revolver will be somewhere around .375 diameter.