I dont see much of a disadvantge at all. Sure your re-loading time is slower than the repeaters, but it is infinitly faster than the muzzel loader, and a lot of folks can fire, restuff the smoke pole, and still get off a second shot. My deer I shot with a 12ga went down to the ground with the first shot, a good 5 seconds later it finaly got to its feet and I then let fly again (which, I later found, was not necessary.) So, no no no, you are at NO disadvantage.
Good day,
Brian