.338 Win Mag.

First introduced in 1958 by Winchester, the .338 Winchester Magnum—commonly known as the .338 Win Mag—quickly earned a lasting place among North America’s most capable big game cartridges. Created by necking down the .375 H&H Magnum case to accept .338-inch diameter bullets, it was designed to deliver a significant power increase over the popular .30-06 and .300 Winchester Magnum, while fitting into a standard-length rifle action. This innovation meant reloaders could experience magnum-class performance without the need for extra-long or heavy rifles. The .338 Win Mag established its reputation for delivering deep penetration and high energy, making it extremely effective on large and tough game, especially in the rugged environments of Alaska and the American West.

The .338 Win Mag’s versatility is one reason it continues to be a favorite with ammunition reloaders. In hunting applications, it is particularly valued for its stopping power on heavy-bodied animals such as moose, elk, and bear. This round is known for its flat trajectory, manageable recoil for its power level, and excellent terminal performance, which are crucial for hunters pursuing game where decisive performance is essential. Beyond North America, it has also proven itself on plains game in Africa and red stag in New Zealand. Reloaders appreciate that the cartridge adapts well to bullets of varying constructions—bonded, monolithic, soft points—tailoring loads for everything from long-range shots across wind-swept valleys to up-close brush encounters.

The primary target species for the .338 Win Mag include moose, elk, bear, and other large-bodied game. Its heavy bullet options and deep penetration make it a top choice whenever hunters need to ensure reliable expansion and terminal effect on thick-skinned or dangerous animals. While it excels as a hunting cartridge, it is less commonly used for target competitions due to recoil and cost, though it remains a capable performer at extended hunting distances where precision shot placement is critical. Many reloaders also prepare custom loads for backcountry hunting scenarios, taking advantage of the caliber’s power to overcome harsh conditions and imperfect shot angles.

Reloaders can select from a wide range of bullet weights for the .338 Win Mag, with common factory and component offerings ranging from 180 grains up to 300 grains. The most popular choices are typically between 200 and 250 grains, balancing velocity with ballistic coefficient and penetration. Bullets on the lighter end of the spectrum provide flatter trajectories, making them ideal for longer-range shots, while heavier bullets optimize momentum and penetration for truly large or dangerous game. The typical muzzle velocity for a 225-grain bullet is around 2,800 feet per second, producing energy levels above 3,900 foot-pounds. The .338 Win Mag features a belt on the case, aiding in reliable headspacing and extraction, and it operates at a maximum pressure of about 64,000 psi, according to SAAMI specifications. Its robust construction and performance make it a reliable, flexible choice in the field, and a rewarding cartridge for reloaders who want both raw power and accuracy from their magnum rifles.