History
Winchester introduced the .338 Winchester Magnum in 1958, one of the belted magnums that also gave us the .264 and .300 Win Mag. The brief was a hard-hitting medium-bore for the largest North American game, elk, moose, the big bears, sitting between the .30 magnums and the heavy .375s. It worked. The .338 became the most popular cartridge in its caliber and a default for serious big-game work, and it has held that spot for nearly seventy years.
This is a hunting cartridge, not a target round. Load it with heavy high-BC match bullets, though, and it carries energy and bucks wind well enough to reach, which is the angle this page takes.
Lineage
The case is the shortened .375 H&H, the same .532 inch belted body that underlies the .264, .300, and .458 Win Mag. It headspaces on that belt and pushes a .338 inch (8.59mm) bullet. In the hunting class its rivals are the faster .340 Weatherby and .338 RUM and the milder .338 Federal. The .338 Lapua and .338 Norma sit a tier above, in extreme-long-range territory of their own.
Specifications
| Spec | Value |
|---|---|
| Case type | Belted, bottlenecked |
| Bullet diameter | 8.59 mm (.338 in) |
| Neck diameter | 9.37 mm (.369 in) |
| Shoulder diameter | 12.47 mm (.491 in) |
| Belt diameter | 13.51 mm (.532 in) |
| Rim diameter | 13.03 mm (.513 in) |
| Case length | 63.50 mm (2.500 in) |
| Overall length | 84.84 mm (3.340 in) |
| Case capacity | ~86 gr H2O (nominal; varies by brand) |
| Primer size | Large rifle magnum |
| Belted | Yes (headspaces on the belt) |
| Rifling twist | 1 in 10 in (SAAMI standard) |
| Max pressure | 64,000 psi (SAAMI) |
| Recommended barrel | 36 in, 1:10 twist |
Barrel Design
Most rifles in .338 Win Mag wear 24 to 26 inch barrels. That is the sensible length to carry into the field, and it gives up almost nothing in practical performance. The cartridge is reasonably efficient for a magnum, so it never depended on an extreme barrel the way the big overbore .338s do.
This site is about pushing a caliber to its ceiling, so the baseline I'd recommend runs long at 36 inches. Nobody hunts with a barrel that long, but it wrings the last velocity from the case and tightens standard deviation for the heavy-match-bullet experiment the .338 Win Mag can support. Treat 36 inches as the ELR-ceiling setup and 24 to 26 inches as the real-world hunting build.
The 1:10 standard twist stabilizes everything the cartridge feeds, from 200 grain hunting bullets up to the 250 and 300 grain match bullets that matter at distance, so there is no reason to deviate. The tables below are computed at the 36 inch barrel; a 24 inch hunting rifle will read meaningfully slower.
Range Ammo Performance
Norma ORYX · 230 gr Bonded SP $1.93/rd
| Range (yd) | Velocity (fps) | Elevation (mil) | Energy (ft-lb) | Windage (mil) |
|---|---|---|---|---|
| 0 | 2896 | -0.4 | 4283 | 0.5 |
| 100 | 2659 | 0.0 | 3610 | 0.3 |
| 200 | 2434 | -0.4 | 3025 | 0.5 |
| 300 | 2220 | -1.1 | 2516 | 0.8 |
| 400 | 2016 | -2.0 | 2076 | 1.2 |
| 500 | 1825 | -3.0 | 1701 | 1.5 |
| 600 | 1647 | -4.1 | 1385 | 1.9 |
| 700 | 1485 | -5.5 | 1126 | 2.4 |
| 800 | 1341 | -7.0 | 919 | 2.9 |
| 900 | 1221 | -8.9 | 761 | 3.4 |
| 1000 | 1126 | -11.0 | 647 | 4.0 |
| 1100 | 1055 | -13.4 | 568 | 4.6 |
| 1200 | 1000 | -16.2 | 510 | 5.1 |
| 1300 | 955 | -19.3 | 465 | 5.7 |
| 1400 | 916 | -22.8 | 428 | 6.3 |
| 1500 | 882 | -26.5 | 397 | 6.8 |
| 1600 | 850 | -30.6 | 369 | 7.4 |
| 1700 | 822 | -35.0 | 345 | 8.0 |
| 1800 | 795 | -39.7 | 323 | 8.5 |
| 1900 | 770 | -44.8 | 303 | 9.1 |
| 2000 | 746 | -50.2 | 285 | 9.6 |
| 2100 | 724 | -56.0 | 268 | 10.2 |
| 2200 | 703 | -62.1 | 252 | 10.8 |
| 2300 | 683 | -68.5 | 238 | 11.4 |
| 2400 | 664 | -75.3 | 225 | 12.0 |
| 2500 | 646 | -82.6 | 213 | 12.6 |
Muzzle velocity 2896 fps is estimated at 36 in from the 26 in factory figure of 2756 fps at about 14 fps per inch. Expect your own barrel to read a little differently. Velocity is color coded green supersonic, yellow transonic, red subsonic; treat transonic and subsonic rows as approximate.
Match Ammo Performance
HSM Trophy Gold · 300 gr Berger Hybrid OTM Tactical $3.64/rd
| Range (yd) | Velocity (fps) | Elevation (mil) | Energy (ft-lb) | Windage (mil) |
|---|---|---|---|---|
| 0 | 2540 | -0.6 | 4297 | 0.3 |
| 100 | 2441 | 0.0 | 3970 | 0.2 |
| 200 | 2345 | -0.6 | 3663 | 0.3 |
| 300 | 2251 | -1.3 | 3376 | 0.5 |
| 400 | 2160 | -2.2 | 3106 | 0.7 |
| 500 | 2070 | -3.2 | 2854 | 0.9 |
| 600 | 1983 | -4.2 | 2618 | 1.1 |
| 700 | 1897 | -5.3 | 2397 | 1.3 |
| 800 | 1813 | -6.4 | 2190 | 1.5 |
| 900 | 1731 | -7.6 | 1996 | 1.7 |
| 1000 | 1651 | -9.0 | 1815 | 1.9 |
| 1100 | 1572 | -10.4 | 1645 | 2.2 |
| 1200 | 1494 | -11.9 | 1487 | 2.4 |
| 1300 | 1419 | -13.5 | 1341 | 2.7 |
| 1400 | 1345 | -15.2 | 1206 | 3.0 |
| 1500 | 1274 | -17.1 | 1081 | 3.3 |
| 1600 | 1206 | -19.1 | 968 | 3.6 |
| 1700 | 1141 | -21.2 | 868 | 4.0 |
| 1800 | 1093 | -23.6 | 796 | 4.4 |
| 1900 | 1064 | -26.1 | 754 | 4.7 |
| 2000 | 1041 | -28.8 | 722 | 5.1 |
| 2100 | 1020 | -31.7 | 693 | 5.5 |
| 2200 | 1001 | -34.8 | 668 | 5.8 |
| 2300 | 984 | -38.0 | 644 | 6.2 |
| 2400 | 967 | -41.4 | 623 | 6.5 |
| 2500 | 951 | -44.9 | 602 | 6.9 |
| 2600 | 935 | -48.6 | 583 | 7.3 |
| 2700 | 921 | -52.5 | 564 | 7.6 |
| 2800 | 906 | -56.5 | 547 | 8.0 |
Muzzle velocity 2540 fps is estimated at 36 in from the 26 in factory figure of 2400 fps at about 14 fps per inch. Expect your own barrel to read a little differently. Velocity is color coded green supersonic, yellow transonic, red subsonic; treat transonic and subsonic rows as approximate.
Trajectory
FAQ
What barrel length and twist should I run?
For hunting, a 1:10 twist and a 24 to 26 inch barrel, which is how the cartridge is normally built and carried. The 36 inch baseline I'd choose is an extreme-long-range ceiling setup, not a field configuration; the 1:10 twist is correct either way.
Is it belted?
Yes. It headspaces on the .532 inch belt of the shortened .375 H&H case it shares with the .300 and .264 Winchester Magnums. The belt is a hunting-era design choice; modern precision .338s like the Norma and Lapua are beltless.
What is the .338 Winchester Magnum good for?
Large North American game, elk, moose, and the big bears, where bullet weight and energy matter, and capable long-range work with heavy match bullets. It is a hunting magnum first, and that is why it has stayed popular for nearly seventy years.
How does it compare to the .338 Lapua Magnum?
They are different tiers. The .338 Win Mag is a belted hunting magnum in ordinary rifles; the .338 Lapua is a much larger, beltless, extreme-long-range cartridge in heavy purpose-built rifles. The Lapua reaches far past the Win Mag at far higher recoil, cost, and rifle weight.