When Winchester introduced the .338 Winchester Magnum in 1958, they set a standard for the serious elk cartridge that still hasn't been surpassed in any meaningful way. It launches 225 to 250-grain bullets at velocities that produce devastating terminal performance on large North American game, with enough case capacity to feed those bullets at long range without going full magnum-heavy the way the .300 Ultra Mag or .338 Lapua do. It fits in a standard long-action rifle. It's practical, proven, and deadly.

Oregon elk hunters who've committed to the .338 Win Mag have made a good decision. Reloading it unlocks the full potential of the cartridge—letting you tune velocity, bullet choice, and seating depth to your specific rifle, hunting application, and tolerance for recoil.

Brass and Case Prep

Winchester and Nosler brass are the go-to choices for most .338 Win Mag reloaders. Lapua now offers .338 Win Mag cases and they're excellent—more consistent primer pockets, tighter tolerances, and longer case life. They cost more, but for a hunting cartridge where you might fire the same cases five to eight times, it's worth it.

Case prep for the .338 Win Mag follows standard large-rifle-magnum protocol:

  • Full-length size unless you're loading for a single rifle and want to neck-size only.
  • Trim to 2.490 inches (SAAMI max is 2.500"). Most brass will grow to trim length after two or three firings.
  • Deburr and chamfer the case mouth after trimming.
  • Use a large rifle magnum primer (CCI 250, Federal 215, Winchester WLRM). Magnum primers are important here—the large case volume and slow powders benefit from the hotter ignition.
  • Weigh your charges. This isn't a cartridge to throw with a powder measure without verifying on a scale, especially near max.

Powder Selection

The .338 Win Mag does best with medium-to-slow burning powders. The big bore diameter and moderate case capacity need a powder that builds pressure progressively without a sharp spike. Proven choices:

  • IMR 4350 / H4350: The classic choice for 225-grain bullets. H4350 meters beautifully and gives excellent velocity with manageable pressure. Start around 71 grains and work up carefully.
  • RL-19 / RL-22: Reloder 19 and 22 are excellent for this case—good velocity, low ES spreads, and consistent ignition in cold weather. RL-22 tends to work better with 250-grain bullets.
  • H4831SC: Short-cut version of H4831 meters better than the standard cut. Great for the 250-grain class of bullets. Slightly slower burn rate gives a velocity edge with heavier projectiles.
  • IMR 7828 SSC: On the slower end but produces top velocities with 225–250 grain bullets. Worth a look if you're chasing maximum performance and can tolerate slightly dirtier combustion.

Bullet Selection for Elk

This is where the .338 Win Mag really shines. The selection of quality .338-caliber hunting bullets is outstanding:

  • Nosler Partition 225 gr: The old reliable. Controlled expansion, deep penetration, and it feeds flawlessly. For hunting in timber where shots are under 300 yards, this is a hard choice to beat.
  • Swift A-Frame 225 gr: Bonded construction, extremely consistent expansion, and outstanding weight retention. More expensive, but this is a bullet you can stake your tag on.
  • Hornady ELD-X 225 gr: For hunters who want excellent ballistic coefficient for longer shots combined with reliable terminal performance. The Heat Shield tip prevents tip deformation in the magazine.
  • Berger Hybrid Hunter 250 gr: For open-country elk hunters who regularly shoot past 400 yards, the high BC of the 250-grain Berger is compelling. Requires a fast enough twist to stabilize—most .338 Win Mag barrels at 1:10" are fine.
  • Federal Trophy Bonded 210 gr: Lighter option for those who want flatter trajectory and reduced recoil without sacrificing penetration on elk-sized game.

Working Up a Load: Starting Points

Always start at the minimum listed in your manual and work up in 1-grain increments, watching for pressure signs: flattened primers, sticky extraction, or cratering around the firing pin. The .338 Win Mag operates at 64,000 PSI SAAMI max—there's meaningful pressure in this case and you should not be cavalier about load development.

A solid starting point for 225-grain elk loads with H4350 is 68–69 grains, working toward a published max of around 73–74 grains depending on your manual. You'll likely find the best accuracy and pressure balance somewhere in the 71–73 grain range, producing velocities in the 2,800–2,850 fps range from a 24-inch barrel.

Seating Depth and Crimp

Seat hunting bullets to an OAL that clears the rifling by at least 0.030 inches (confirmed with a Hornady OAL tool or equivalent). Magazine length limits you to about 3.340 inches OAL for most rifles. A factory crimp die is optional but helps with recoil dislodgement in tubular magazines and ensures consistent bullet release. For bolt-action hunters, it's less critical.

Final Notes for the Oregon Elk Hunter

The .338 Win Mag is a cartridge that rewards the reloader. Factory ammunition in this caliber is expensive, availability can be spotty, and factory loads don't always print their best groups in your specific rifle. By developing your own loads, you gain cost efficiency, repeatable precision, and the confidence that comes from knowing exactly what's in your chamber when the bull steps out at last light on opening morning.