458 Lott Ammo is a .458 caliber rifle cartridge designed for the purpose of hunting large, thick-skinned dangerous game animals in Africa. It is based on the full length .375 H&H Magnum case blown out and shortened to 2.800 inches (71.1 mm).
The .458 Lott was designed in response to perceived inadequacies and problems encountered with the .458 Winchester Magnum. The cartridge provides a distinct step up in performance over the .458 Winchester Magnum. A-Square, Česká Zbrojovka/Brno, Hornady, and Ruger have been instrumental in the cartridge’s rise in popularity.
The .458 Lott Ammo was designed in 1956 and was an immediate commercial success. It was a more economical alternative to the English double rifles that were considered the standard rifle type for dangerous game hunting in Africa. The .458 Winchester Magnum was designed to emulate the performance of the .450 Nitro Express in a standard-length bolt-action rifle.However, it soon became apparent that the .458 Winchester Magnum was not performing as anticipated. Several factors contributing to its less than stellar performance in Africa: clumping of its compressed powder charge and use in 20–22 in (510–560 mm) barrel rifles.