.455 MK II Load Data

The .455 Mk II caliber holds a significant place in British firearms history, tracing its legacy back to the late 19th century when it was adopted by the British military as a replacement for the .455 Mk I. The .455 Mk II was introduced in 1897, offering improvements over its predecessor, mainly featuring a shorter and more robust case designed to use smokeless powder rather than black powder. This advancement not only improved reliability and safety but also offered more consistent ballistic performance. The caliber was widely chambered in the iconic Webley revolvers, which became synonymous with British and Commonwealth forces during pivotal historical moments, including World War I and World War II. Respected for its manageable recoil and effective stopping power at close range, the .455 Mk II continued in military service until gradually replaced by smaller, faster cartridges like the .38 S&W in the mid-20th century.

Reloaders and enthusiasts are drawn to the .455 Mk II for its unique balance of history and practicality. While its original military application revolved around service revolvers, today this caliber is frequently used in historical reenactments, competitive shooting, and collecting. The soft-shooting characteristics make it particularly attractive for shooters seeking a classic revolver experience without harsh recoil. Additionally, enthusiasts restoring or maintaining vintage Webley and similar revolvers rely on the .455 Mk II, appreciating its period-correct authenticity and the satisfaction of firing a piece of living history. Given the caliber’s relatively mild performance, handloaders are able to create dependable, accurate ammunition while maintaining safe pressures for aging firearms, making reloading both a practical necessity and a rewarding hobby.

When considering target species, the .455 Mk II is primarily a cartridge for recreational and historical shooting rather than hunting. Its moderate energy and large bullet diameter lend it more toward defensive and target shooting roles, as was intended during its military service. Although the round can humanely dispatch small to medium game at close distances in an emergency, it is not typically selected for hunting purposes. Instead, shooters use it for steel target shooting, plinking, and engaging paper targets. Collectors and competitive shooters alike value the cartridge’s controllable recoil and distinctive, authoritative firing signature, which adds to the enjoyment of range sessions with classic handguns.

Typical bullet weights for the .455 Mk II run from 262 to 265 grains, traditionally utilizing round-nosed or flat-nosed lead projectiles. The standard cartridge operates at relatively low pressures—generally around 12,000 CUP—helping to preserve the integrity of older revolvers and maintaining a gentle recoil impulse. The caliber’s nominal bullet diameter is .455 inch, though actual measurements may range from .454 to .456 inches depending on mold or manufacture variances. With velocities hovering between 600 and 700 feet per second out of a standard 6-inch barrel, the .455 Mk II delivers adequate stopping power for its intended purposes while remaining gentle on both shooter and gun. This combination of manageable ballistics, historical context, and adaptability for reloading continues to make the .455 Mk II a cherished choice among discerning revolver aficionados and vintage ammunition reloaders.