A Ruger #1 is a great platform for the .45/70, but since it's also a great platform for the .458, if it was my money, it would be a .458. One of the Marlins is a good option, at one time I had one of the earlier blue and walnut M-1895 versions, with the 22" micro-groove barrel, a straight stock, and half magazine. In those days cash money was an issue, and a M-700 in .30/06 seemed like a more practical outfit, so the Marlin got traded off. I keep hearing how the .45/70 is the equal of the .458, but I've yet to see it prove out. In the Marlin, the OAL is restricted to a pistol bullet profile, but with the bullet seated out in the #1, there'd be more room for propellant. Still, a .45/70 that's busting at the seams is still no .458, but a .458 can be backed off to fill the .45/70 niche. If I was intent upon a .45/70 repeater, I might take a hard look at one of the modern manufactured '86 Winchesters from Browning, Pedersoli, or Uberti.