From my understanding, .44 is the minimum, .480 ruger packs more of a whollup than a .454 casulli and kicks less. My 2 choices are .44 or the .480, though I believe CZ makes a sweet sidearm chambered for up to some .44 supermag or 455 supermag, think it also will shoot .45 ammo.

Also you know what they say...."file off that front site, you won't want to cut your lip on it when it's in your mouth and that griz is charging!"