Turning off the rim on loaded factory ammo is better than hand loading? I could do it on my tool room lathe, but I do not know if you could do it on the 9x20 lathe that would fit in an apartment.
I will look later for some 45/70 ammo at the house.

I did add both drawings to this post, what you are asking does not look easy. Even if you can modify the rims to fit a Krag bolt I am fairly certain they will not feed without extensive modifications to the side plate and perhaps the receiver.
Here is a link to the SAAMI drawings you can look at them or print them and I do not have to worry about copyright infringement.
  (You need to Login