Well, sure, but black powder weapons do not lend themselves to criminal activity.
A claw hammer would probably be a more effective weapon if you were looking to take up a life of mayhem.
If you were looking to 'disarm" criminals, you would have to prohibit kitchen knives, many tools, household chemicals and even automobiles.
Black powder should be exempt because you have to draw the line somewhere.
Anyway, a criminal act should be a crime because it is a criminal act. Robbery, rape, assault and murder are the crimes, whether they are committed with a weapon, brute force or whatever. Making mere possession of firearms illegal just creates new crime and makes new criminals.
Remember Frank and Jessie James?