Calling modern muzzleloading propellants "black powder substitutes" for many of the rifles that they were designed to be used in is just stupid. Many of these pellet formed propellants were never intended to be used in a black powder era design gun.
Holy Black has as much place in these modern rifles as it does in a modern cartridge firearm. Could you use it, sure you could. Would you then call it a smokeless powder substitute ?
Pyrodex is probably one of the very few so called black powder substitutes left. I have read all the "horror stories" here about it and they are all very amusing. Pyrodex is everything Hodgdon ever claimed it was and if you fallow their directions for its use you will never have any trouble.
Today's modern muzzleloading propellants are made for today's modern mostly inline and primer ignited rifles. Some of these propellants can be safely used in black powder era designed guns but to call them black powder substitutes is just simply wrong.
You could call them black powder alternatives I guess but let's stop this "substitute" BS.
Motor