I doubt Bambi would be able to tell which headstamp was on the brass that was fired the bullet, 450M or 45-70, although the 45-70 has slightly larger case capacity.
450M brass is still only made by Hornady...
If I wanted the mostest from either cartridge I'd get a Ruger #1, not made in 450M so it would be 45-70...
Which will be here in 20-50 years, 45-70!

"Camping places fix themselves in your mind as if you had spent long periods of your life in them.
You will remember a curve of your wagon track in the grass of the plain like the features of a friend."
Isak Dinesen