.475 Barnes Supreme (P.O. Ackley Data)

.475 Barnes Supreme (P.O. Ackley Data)

The .475 Barnes Supreme is a powerful wildcat cartridge developed during the mid-twentieth century and documented through the work of P.O. Ackley. It was designed as a large-bore dangerous-game cartridge, emphasizing heavy bullet weight, high velocity and deep penetration. The cartridge reflects the period’s interest in pushing the limits of performance using improved case designs, while maintaining reliable operation in strong bolt-action rifles intended for use on the largest and most dangerous game animals.

The .475 Barnes Supreme is generally based on a belted magnum case derived from the .375 Holland & Holland Magnum, modified in accordance with Ackley-style principles. These modifications typically include reduced body taper and a sharper shoulder angle to increase case capacity and improve efficiency. The case is necked to accept .475-inch bullets, providing substantial frontal area and allowing the cartridge to take advantage of heavy bullet weights. Data associated with Ackley’s work commonly includes bullet weights ranging from approximately 400 to 500 grains, with velocities capable of exceeding 2,300 feet per second depending on the specific load and rifle configuration.

Designed for dangerous-game hunting, the .475 Barnes Supreme offers significant energy and penetration, making it suitable for animals such as elephant and Cape buffalo. The combination of large bullet diameter, heavy weight and high velocity allows for deep, straight-line penetration through dense muscle and heavy bone. Bullet selection is critical to performance, with solid projectiles favored for maximum penetration and controlled-expansion bullets used when greater tissue damage is desired.

Recoil is considerable, reflecting the cartridge’s high performance and intended purpose. Rifles chambered for the .475 Barnes Supreme are typically heavy bolt-action designs built to safely handle the pressures and recoil associated with large-caliber cartridges. Proper stock design and rifle weight are essential for managing recoil and ensuring effective operation in the field. As with other Ackley-documented cartridges, careful attention to chambering and loading practices is necessary to achieve consistent and reliable performance.

The .475 Barnes Supreme remains a relatively uncommon cartridge, primarily of interest to enthusiasts of large-bore wildcats and historical cartridge development. As reflected in P.O. Ackley’s data, it represents an example of mid-century experimentation aimed at increasing power and efficiency, contributing to the broader evolution of modern dangerous-game cartridges.

Source: Wolfe Publishing (P.O. Ackley Data)