Some years ago, in the 90's, a fellow re-barreled or re-bored a 7.62X54R and chambered it for the .50 Alaskan. He wrote it up in Precision Shooting. It was a light rifle due to the thin barrel walls, and of course a 450gr. bullet at over 2,000fps kicked quite a lot in the 7 pound rifle. I've still got the article, somewhere if anyone's interested.

BTW - same rim diameter as a .45/70, but of course, uses a straighted .348 WW case.