.338 Winchester Magnum
The .338 Winchester Magnum is a .338 in (8.6 mm) caliber, belted, rimless, bottlenecked cartridge introduced in 1958 by Winchester Repeating Arms. It is based on the blown-out, shortened .375 H&H Magnum. The .338 in (8.6 mm) is the caliber at which medium-bore cartridges are considered to begin. The .338 Winchester Magnum is the first choice among professional brown bear (specifically grizzly bear) guides in Alaska to back up clients where a powerful stopping caliber is required on charging bears. It is also the most popular medium-bore cartridge in North America and has the most widely available choice in rifles among medium bore rifles. The action length is the same as a .30-06, and most major rifle manufacturers in the United States chamber rifles for the cartridge including the semi-automatic Browning BAR Mk II Safari, making it a very powerful combination against charging dangerous game. The cartridge was intended for larger North American big-game species and has found use as for the hunting of thin-skinned African plains-game species.
| .338 Winchester Magnum | ||||||||||||||||||||
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.375 H&H Magnum (Left) .338 Winchester Magnum (Right) US Quarter for scale | ||||||||||||||||||||
| Type | Rifle | |||||||||||||||||||
| Place of origin | USA | |||||||||||||||||||
| Production history | ||||||||||||||||||||
| Manufacturer | Winchester Repeating Arms | |||||||||||||||||||
| Produced | 1958 | |||||||||||||||||||
| Specifications | ||||||||||||||||||||
| Parent case | .375 H&H Magnum | |||||||||||||||||||
| Case type | Belted, bottleneck | |||||||||||||||||||
| Bullet diameter | .338 in (8.6 mm) | |||||||||||||||||||
| Neck diameter | .369 in (9.4 mm) | |||||||||||||||||||
| Shoulder diameter | .491 in (12.5 mm) | |||||||||||||||||||
| Base diameter | .513 in (13.0 mm) | |||||||||||||||||||
| Rim diameter | .532 in (13.5 mm) | |||||||||||||||||||
| Rim thickness | .050 in (1.3 mm) | |||||||||||||||||||
| Case length | 2.500 in (63.5 mm) | |||||||||||||||||||
| Overall length | 3.340 in (84.8 mm) | |||||||||||||||||||
| Case capacity | 86 gr H2O (5.6 cm3) | |||||||||||||||||||
| Rifling twist | 1-10" | |||||||||||||||||||
| Primer type | Large rifle magnum | |||||||||||||||||||
| Maximum pressure | 64,000 psi | |||||||||||||||||||
| Ballistic performance | ||||||||||||||||||||
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| Test barrel length: 24 Source(s): Accurate Powder | ||||||||||||||||||||