I'd go with .450 Marlin. Works with a standard magnum bolt face, fits and feeds from a standard magnum magazine. Load it down to 45-70 levels or crank it up to its full potential. The Hornady plastic-tipped pointy bullets let you reach out past 200 yards. In any case, it would be a great cartridge for a bolt rifle.

Ammo much easier to come by.

Am unsure whether it would fit in a short action; If so, I may have a barrel for my model 16 made up in .450 Marlin.