I like my FA M83 in .454. It can shoot low-recoiling .45 Colt rounds, but FA strongly recommends sending in the revolver to have a second custom-fitted .45C cylinder made for the gun. They say something along the lines that, because of the tight tolerances, shooting a 45C out of your FA .454 cylinder can lead to fouling that can make the pressures rise to an unsafe level. Some say it’s BS, some say it isn’t. Don’t know who is correct.

But, in any event, even with .454 loads, you can shooting anything from the equivalent of a modestly-loaded .44 Mag (https://www.midwayusa.com/product/2900213587?pid=213587) to full-bore antitank rounds: https://www.midwayusa.com/product/1021047880?pid=566326

Beautiful gun too:

[Linked Image from i.imgur.com]