.458 Lott - Design & Specifications

Design & Specifications

The objective behind the design of the .458 Lott was to provide a greater case capacity over the .458 Winchester Magnum so as to provide better performance and less compression of the powder charge. The .458 Lott achieved both these objectives by its lengthened cartridge. Furthermore, as the Lott cartridge is in essence a lengthened .458 Winchester Magnum, converting a .458 Winchester Magnum to .458 Lott involves in many cases a simple re-boring of the chamber and if required, a lengthening of the magazine.

The .458 Lott was standardized by SAAMI in 1995 based on specification provided by Arthur Alphin and A-Square LLC. According to Arthur Alphin, the cartridge length was standardized at 2.800-inch (71.1 mm) and the chamber length at 2.810-inch (71.4 mm) because there were many converted rifles in the field that were chambered for the original Jack Lott length. The specifications published by SAAMI reflect this fact.

The specifications for the .458 Lott call for a cartridge which gradually tapers. However, A-Square and few other ammunition manufacturers provide a ghost shoulder for the cartridge which was not included in the specification as standardized by SAAMI. Arthur Alphin chose not to include the ghost shoulder to remain true to Jack Lott's wishes and to honor his memory. The ghost shoulder serves to provide better retention of the bullet in the case under recoil. Like A-Square .458 Lott cartridges, Barnes .458 Lott brass bears a ghost shoulder for this very same reason.

SAAMI compliant .458 Lott cartridge schematic: All dimensions in inches .

SAAMI recommends a 6 groove rifling contour with each grove being .150-inch (3.8 mm) wide. Distance between lands is .450-inch (11.4 mm) and between grooves is .458-inch (11.6 mm). Recommended rifling twist is between 1:10 to 1:20. Most rifle manufacturers use 1:14 or 1:16 twist rates.

Since Lott was an influential big-game hunter and writer the cartridge gained some attention with professional hunters in Africa. The .458 Lott was soon commercialized by A-Square as a proprietary cartridge. CZ chambered the cartridge in their BRNO ZKK 602 rifles based on the Magnum Mauser action. However, the Lott remained fairly obscure at least in the United States until Ruger offered the cartridge in their Ruger M77RSM Mk II rifles to the American public in 2002. Since then there has been a slow but steady movement away from the .458 Winchester Magnum towards the .458 Lott among professional hunters heading to Africa.

The .458 Winchester Magnum is ubiquitous in Africa. While one might not be able to easily find ammunition for the big Weatherby or the Nitro Express cartridges, due to its popularity one would be able to find .458 Winchester Magnum cartridges. In an emergency, the .458 Winchester Magnum can be fired in the chamber of a .458 Lott.