.338 Rem. Ultra Mag Load Data

The .338 Remington Ultra Magnum, often abbreviated as .338 RUM, is a powerful rifle cartridge developed by Remington Arms and introduced in 2000. Designed to meet the demand for a hard-hitting, long-range hunting round, this cartridge is based on the Remington Ultra Magnum family, which in turn traces its roots to the .404 Jeffery case. By necking down the large, beltless Ultra Magnum case to accept .338-inch bullets, Remington created a cartridge that rivals other heavy hitters like the .338 Lapua Magnum and the .340 Weatherby Magnum, delivering top-tier performance for serious big-game hunters and long-range shooting enthusiasts alike.

In terms of application, the .338 Rem. Ultra Mag. is renowned for its exceptional performance in hunting scenarios that demand both extended range and substantial stopping power. It excels in open terrains such as mountainous regions and tundra, where long shots are common and the need to anchor large animals with authority is paramount. While it is somewhat overpowered for North American whitetail deer or similar-sized game, its true forte lies in hunting the largest and most resilient game animals like elk, moose, and especially bears. Reloaders turn to the .338 RUM when they need flat trajectories, high retained energy at distance, and deep-penetrating power suitable for ethical long-range harvests.

Target species for the .338 Remington Ultra Magnum are primarily large, tough-bodied animals. It's a favorite among guides and hunters operating in Alaska and the northern Rockies, where encountering brown bear, grizzly, and moose is commonplace. The cartridge is capable of cleanly taking these heavyweights due to its significant energy reserve, even at ranges exceeding 400 yards. On expeditions for African plains game or hunting exotic species like musk ox and bison, the .338 RUM’s hard-hitting performance instills confidence in those who need to make critical, one-shot stops. For reloaders tailoring loads to their quarry, the versatility of bullet selection is a key advantage.

Typical bullet weights for the .338 Remington Ultra Magnum range between 200 and 300 grains, with the 225- to 250-grain bullets being especially popular for their balance of velocity, penetration, and expansion. High-quality, bonded-core or monolithic bullets in this weight class retain mass for deep penetration, crucial when targeting large species. Velocities with factory ammunition can reach up to 3,150 feet per second with 225-grain bullets and around 2,900 feet per second with 250-grain projectiles. The .338 RUM is also known for its relatively flat trajectory and high ballistic coefficients, factors that are attractive to reloaders interested in maximizing downrange accuracy and terminal performance. While recoil and muzzle blast are substantial, many shooters appreciate the round’s ballistic superiority and the confidence it inspires on demanding hunts.