338 Winchester Magnum
.TheΒ .338 Winchester MagnumΒ is a .338Β in (8.6Β mm) caliber, belted, rimless, bottlenecked cartridge introduced in 1958 byΒ Winchester Repeating Arms. It is based on the blown-out, shortened .375 H&H Magnum.[2]Β The .338Β in (8.6Β mm) is the caliber at which medium-bore cartridges are considered to begin.
The .338 Winchester Magnum is the first choice among professionalΒ brown bearΒ (specificallyΒ grizzly bear)Β guidesΒ inΒ AlaskaΒ to back up clients where a powerful stopping caliber is required on charging bears.[3]Β It is also the most popular medium-bore cartridge in North America[4]Β 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-automaticΒ Browning BARΒ Mk II Safari, making it a very powerful combination against charging dangerous game.[5][6]
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.[1]
The .338 Winchester Magnum traces its heritage to the experiments conducted by Charles O’Neil, Elmer Keith and Don Hopkins with cartridges firing .333Β in (8.5Β mm) bullets in the late 1940s.
The use of .333Β in (8.5Β mm) bullets may seem odd today but at the time this was the standard diameter of European .33 caliber bullets which were more common than the .338Β in (8.6Β mm) diameter bullets used in cartridges such as the .33 Winchester.
Furthermore, the .333Β in (8.5Β mm) were available in heavier weights than the .338Β in (8.6Β mm) bullets. O’Neil, Keith and Hopkins experiments led to the creation of the .333 OKH, which was based on theΒ .30-06 SpringfieldΒ case necked up to accept .33 caliber bullets and the .334 OKH which used a shortened .375 H&H Magnum necked down to accept the same bullets.
The .338 Winchester Magnum was introduced in 1958 together with theΒ .264 Winchester MagnumΒ and theΒ .458 Winchester Magnum, all of which used a common case design based on the .375 H&H Magnum case blown out and shortened to 2.500Β in (63.5Β mm), much like the .334 OKH
. When the cartridge was introduced, Winchester offered a 200Β gr (13Β g) at 3,000Β ft/s (910Β m/s), a 250Β gr (16Β g) at 2,700Β ft/s (820Β m/s) and a 300Β gr (19Β g) at 2,450Β ft/s (750Β m/s). Sometime later, Winchester introduced the Winchester Model 70 Alaskan chambered for the cartridge.
This chambering left little doubt that the cartridge was intended for big heavy dangerous game.
The .338 Winchester Magnum follows the modern cartridge designs in that the cartridge case features a case with minimal taper so as to maximize case capacity yet providing reliable feeding and extraction.
The .338 Winchester Magnum is based on the .375 H&H Magnum, which was shortened to 2.500Β in (63.5Β mm), blown out and necked down to hold a .338Β in (8.6Β mm) bullet. The case has a capacity of 86.0 grain of H2O (5.58Β cm3).
The cartridge follows the design of the standard length Weatherby Magnum cartridges such as theΒ .257 Weatherby Magnum,Β .270 Weatherby MagnumΒ and theΒ 7 mm Weatherby MagnumΒ for which Winchester had supplied basic brass until 1948.
Performance[edit]
This cartridge is able to push a 225-grain (14.6Β g)Β bulletΒ toΒ velocitiesΒ of 2,800Β ft/s (850Β m/s), generating 3,918Β ftβ lbf (5,312Β J),[7]Β providing energy values at 200 yards that are roughly equivalent to theΒ .30-06 Springfield‘s energy values[8]Β atΒ muzzle. Bullets are available in a very wide range of designs and weights ranging from 150[9]Β to 300 grains.Β SAAMIΒ pressure level is 64,000Β psi.
338 Winchester Magnum is capable of launching heavier bullets than the .30 caliber (7.62mm) cartridges. The most common bullets loaded for the .338 Winchester range from 200Β gr (13Β g) to 250Β gr (16Β g). Typical bullet weights for factory ammunition are 200Β gr (13Β g), 210Β gr (14Β g), 225Β gr (14.6Β g) and the 250Β gr (16Β g).
Typical velocities for these bullet weights range from 2,960Β ft/s (900Β m/s) for the 200Β gr (13Β g) to about 2,660Β ft/s (810Β m/s) for the 250Β gr (16Β g) bullet each generating approximately 3,900Β ftβ lbf (5,300Β J) of energy.
This is approximately 25% more energy generated than the 30-06 Springfield.
Key Specifications
- Item Number: 97339
- Mfg. Number: P338B2
- UPC: 029465084837
- Caliber: .338 Winchester Magnum
- Bullet Weight: 250 grain
- Bullet Style: NP
- Muzzle Velocity: 2,660 FPS
- Muzzle Energy: 3,925 ft.-lbs.
- Case Type: Nickel plated
- Primer Type: Boxer, reloadable
- Corrosive: No
- Rounds: 20





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