I don't know how much hassle it would be to clean the fouling out of the workings of a lever action after shooting bp, but I don't imagine you can just dunk them in hot water and pump the barrel a bit. Maybe someone who has and does could comment on it. Bp and most of the substitutes are dirty and messy in use, and you can't wait for a few days before cleaning as the residues are also corrosive.
A bolt action or a single shot might require removal of the stock, unless the ss is a break action. Despite my misgivings about the H&R's, they would be very easy to clean. With a m/l with hooked breech, it's a simple matter to take off the barrel and clean it. Only the hammer really needs anything more than wiping down, and that's a minute or two with a few qtips.