The .450 Marlin is a firearms cartridge designed as a modernized equivalent to the .45-70 cartridge. It was designed by a joint team of Marlin and Hornady engineers headed by Hornady's Mitch Mittelstaedt, and was released in 2000, with cartridges manufactured by Hornady and rifles manufactured by Marlin, mainly the Model 1895M levergun. The Browning BLR is also now available in .450 Marlin chambering, as is the Ruger No. 1. Marlin ceased manufacture of the 1895M rifle in 2009. In October 2022 it was rumored that Ruger Firearms, the new owner of Marlin Firearms, may be reintroducing the 450 Marlin in their Model 1895 guide gun, but this has not been confirmed by Marlin or Ruger.

The .458 Winchester Magnum is a belted, straight-taper cased, Big Five game rifle cartridge. It was introduced commercially in 1956 by Winchester and first chambered in the Winchester Model 70 African rifle. It was designed to compete against the .450 Nitro Express and the .470 Nitro Express cartridges used in big bore British double rifles. The .458 Winchester Magnum remains one of the most popular large game cartridges, and most major ammunition manufacturers offer a selection of .458 ammunition.