Sounds a great idea EDELWEISS!

To get a rifle to fit that cartridge, I'm not sure if the Ruger will fit it - however if it can then a ream job will be the go on a .45-70 or .458WM!
You may have to get a special reamer, definitely best speaking with a reamer mob for this one!
Mind you if you can get it into a Ruger & load it up properly it will be a fearsome beast!
It has an ENORMOUS case capacity!