.338-378 Weatherby Ammo

The .338-378 Weatherby Magnum (WBY) is a high-powered, long-range rifle cartridge designed for hunting large game and precision shooting. Developed by Weatherby in 1998, this cartridge is based on the .378 Weatherby Magnum case, which has been necked down to accept .338 caliber bullets. The .338-378 WBY was specifically designed to deliver increased velocity, energy, and long-range performance compared to other .338 caliber cartridges on the market.


The .338-378 WBY features a belted, bottleneck case design with a bullet diameter of .338 inches (8.59mm). Bullet weights for this cartridge typically range from 225 to 300 grains, with the most common choices being 250 and 300-grain projectiles. Muzzle velocities for the .338-378 WBY can exceed 3,000 feet per second, depending on the bullet weight and powder load.

The .338-378 WBY has earned a reputation for its exceptional performance on large and dangerous game, such as elk, moose, and African plains game. Its high ballistic coefficient, combined with substantial energy transfer and penetration, makes it a reliable choice for hunters seeking a cartridge capable of taking down big game at extended ranges. Moreover, its flat trajectory and resistance to wind drift make it a popular option for long-range precision shooting enthusiasts.

Ammunition manufacturers offer a variety of projectiles for the .338-378 WBY, including traditional soft point, polymer-tipped, and monolithic bullets. This variety allows shooters to select the most suitable ammunition for their specific needs, ensuring optimal performance in diverse hunting or shooting situations.

In summary, the .338-378 Weatherby Magnum is a powerful and highly capable rifle cartridge designed to deliver exceptional long-range performance and versatility. Its impressive combination of speed, energy, and accuracy has made it a popular choice among big game hunters and precision shooters alike, solidifying its place as a top-tier cartridge in the shooting world.

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