I'll bite.

Actually, any bolt gun capable of handing a standard belted magnum ctg. can easily work with the .450 Marlin, the belted magnum modern version of the old 1873 era 2.1" 45/70.
THE .450 Marlin is the 'modern' commercial equivalence to my old .458 2" "American", a wildcat ctg. of the 50's I expect.

In my VZ34 action with 22" bl. I ran the same powder charge with 350, 400 and 500gr. jacketed bullets in my .458 2", achieving 2,296fps, 2,170fps and 2,059fps respectively.

Strung out near max. in a bolt action rifle, they can easily best 2,300fps with 350's and 2,200fps with 400's.
The 500gr. Hornady at 2,059fps was very close to a maximum load.

My loads gave duplicate velocities in a friend's 24" .45/70 Argentine Mauser I helped him build back in the late 70's.

Done up in a bolt gun, there are no flies on the old .45/70 (.450 Marlin)

Even better, is the .458 Alaskan, my rebated rim version of the .450 Alaskan. It easily made over 2,150fps with 500gr. Hornadys- form the 2.1" .348 case blown out with rim turned to .532" and new extractor groove cut. I sold the rifle but still have the brass - 50 to 100 rounds of it, not sure #.