I think that you might be asking an open ended question.
First off, when you ask "....versus that of the controlled and measured propellant amount used within the jacket of a bullet.", I think that you mean within a bullet case versus loading the black powder manually.
Are you trying to compare the velocity of a patched round ball fired from a muzzle loader to a bullet fired from a black powder cartridge gun, and if so which caliber?
Would it be fired from a rifle, single shot pistol or a revolver?
Please try to provide more details for us to better understand the question and the full context of your hypothetical scenario.
The amount of powder loaded, the length of the barrel and the comparative weights of the bullets and size of the case (if any) are all factors to be considered.