Yes, the Marlin 1895 can accommodate the .610" rim. The 45-70's rim is .608".How about an 1886 in 50/110 or 50/90. Don't know for sure but I don't know if the 1895 bolt face can be opened up enough for the 348 Winchester rim.
He is looking to build it himself as a student of gunsmithing.
would the standard 1-20 twist be fast enought for 500+ grain bullets or not really