.340 Weath. Mag. Load Data

Introduced to the shooting world in 1963, the .340 Weatherby Magnum (commonly referred to as the .340 Wby. Mag.) is a high-powered, belted rifle cartridge designed by Roy Weatherby and manufactured by Weatherby Inc. This cartridge was developed to provide hunters and shooters with improved velocity, flat trajectory, and greater energy over the .338 Winchester Magnum. Designed around the famed .300 Weatherby Magnum case, the .340 Weatherby Magnum features a necked-up design to accept .338 caliber bullets, resulting in increased downrange performance without requiring a correspondingly larger rifle action. While sometimes overshadowed by other magnum cartridges, the .340 Weatherby Magnum has built a loyal following among dedicated big game hunters and reloaders who value its outstanding long-range capabilities and ballistic excellence.

The .340 Weatherby Magnum’s primary application lies in big game hunting, particularly where shots at game may be taken at extended ranges. Its high velocity and energy make it exceptionally suitable for North American big game species. It has found favor among hunters pursuing elk, moose, and large bears, as well as African plains game. The cartridge’s inherent power, combined with Weatherby’s signature double-radius shoulder, delivers impressive terminal performance and quick, humane results even on large-bodied animals. The .340 Wby. Mag. maintains a flatter trajectory and more retained energy at distance compared to many competitors, making it a preferred option for reloaders and hunters who may encounter a variety of challenging hunting environments.

When considering target species, the .340 Weatherby Magnum is a superb choice for any large North American game, including elk, moose, bison, and the largest bears such as grizzly and brown bears. Its powerful ballistics are more than sufficient for driving heavy, controlled-expansion bullets through thick muscle and bone, making it ideal for dangerous game where deep penetration and weight retention are critical. With the right projectile, the .340 Wby. Mag. can also be utilized for African plains game of similar size and toughness, such as eland and kudu. While it may be considered excessive for deer-sized game due to its power, careful bullet selection and handloading can allow for tailored loads when versatility across species is a priority.

In terms of bullet weights and caliber characteristics, the .340 Weatherby Magnum is commonly loaded with bullets from 200 to 250 grains, with 225- and 250-grain projectiles being especially popular among reloaders targeting heavy game. The cartridge’s large powder capacity and high operating pressures allow it to push these bullet weights to impressive velocities—often exceeding 3,000 feet per second with 225-grain bullets. The .340 Wby. Mag. maintains excellent energy retention and wind-bucking capability at long range, attributes further enhanced when using streamlined, high ballistic coefficient bullets. Reloaders appreciate the cartridge’s flexibility, as it responds well to a range of projectile choices and seating depths. However, such performance comes with commensurate recoil and muzzle blast, making it best suited to experienced shooters comfortable with magnum-level cartridges and robust rifle platforms. For those seeking top-of-the-line .338 magnum performance, the .340 Weatherby Magnum stands as a proven and formidable choice.