i don't see why not. if i recall correctly the case was oeiginally made from 348 winchster. i would think a barrel and a 45/70 ruger extractor and a smith that wanted to install the new barrel and you would be good to go. i believe the biggest stumbling block would be to find some one who had the reamer or that would just be another cost for you.
why not just do it in 50 Alaskan and then you can shoot both. Or take it to the next step and do 50-110 and shoot all three.
Dave
I'm ignorant when it comes to these calibers. I just want to find something I could shoot in a rifle that I'm already shooting with the pistol so I can just load all the same