I think the 475 GNR round is the sanest big bore conversion for the Marlin leverguns. It should really get a job done in quick fashion. More velocity in than the same weight bullets in 45cal. The 50 Alaskan is just too brutal to be enjoyable. All this from someone that uses a 45-70 in a #3 Ruger. The Ruger is lighter then the Marlins. A great little walkabout gun.