: Obviously, the .348 case, blown to Improved will fit in the Marlins. I wonder if any crow-bar work is needed. Perhaps not much, now that I think on it. The rim dia is almost identical to the 45-70.
: The extra recoil might require different attachment of the mag. tube.
: The extra capacity shows with the improved ballistics they got.
: I had a 50 Alaskan at one time in a single shot rifle, a wonderful shooter and loads are available in the new Hodgdon yearly hand book. With cast bullets and tang sight, I got 1-1/2" at both 100 and 200 yards for 5 shot groups. My best bullet weight was 520 Lyman and 550gr.RCBS cast bullets in a 24" twist McGowen barrel.
: This Big .50 is a potent round and the one I'd barrel up as the .458 version is only 100 to 150fps better than the .45-70. The .50 will give added diameter and velocity with deeply penetrating, heavy bullets. 50-70 dies will work, and are available from www.trackofthewolf.com . If full elngth sizing of the brass is required, CH4D sells .50 Alaskan dies for around $89.00 I think.