a 1873 set up to shoot 45 acp will chamber and shoot 455 fiochhi.
agreed. however, if you tell people, especially cops, that its still chambered in an antique caliber instead of the modern caliber it just happens to also shoot, I would think you're less likely to be hassled with having an "unregistered handgun" if you were carrying it in the bush, say, or shooting on crown land with it. Mind you, having all the paperwork in order anyway would be smart. get my point?