Go with the Marlin 1894, the barrels have a 1:20 rate of twist that will stabilize very heavy bullets from jacketed to cast variety plus you'll have a wider selection of after market parts if you want to slick up the action even more. The CB II model is no longer made but they came with a 24 inch octagonal barrel and is essentially the exact same thing as the current production cowboy rifles. I don't know if Marlin chambers the .45 Colt for the round barrel models or not, which is usually cheaper.