Cartridge, Hmmmm? Lets see 45-70 would be the easy button but maybe something a bit shorter. Id certainly prefer bigger. How'bout 50-70? Theres always 500S&W if youre open to smokeless
I did this for someone a couple of weeks ago
Not a break open gun, and not a cartridge that I'm longing for as a hunting gun for myself, but since you mentioned hyphenated cartridges I figured I'd put that up for kicks...