Ted - pretty much what I was wondering, but I was thinking somewhat in reverse.
I thought that smokeless was a more powerful powder than black, that you needed less of the smokeless to accomplish the same task. I attributed the fact that you can still hear the smokeless powder shake around in a typical x54r load to smokeless being more powerful (as well as cleaner).
Though I have heard that, if one is to make up handloads with black powder, to be sure and leave no air pockets, as that creates a mini-bomb in the chamber.
Being an ex-city boy, I'm still pretty new to the details of black powder