The .338 Winchester Magnum
February 20, 2019
Prior to 1958, the average North American hunter whose prey required a round more capable than the .30-06 but less powerful and expensive than the .375 Holland & Holland was confronted with limited options. The only standardized .30-caliber Magnum that was available in the United States at the time was the .300 H&H; the .300 Weatherby Magnum was still a proprietary cartridge. Additionally, rifles and ammunition for either cartridge were usually expensive.
Although excellent custom wildcats served that niche, remember we are talking “average hunter on a budget.” The commercial cartridges between two .30-caliber Magnums and the mighty .375 H&H were old and anemic. The .33 Winchester, .348 Winchester, and .35 Remington that dominated this sector were usually chambered in lever-action or slide-action rifles, so performance was limited. Even the latecomer .358 Winchester (1955) struggled to break 2,300 fps when firing 250-grain bullets from sporting rifles.
In 1958 Winchester resurrected the bullet diameter it had used in the discontinued .33 Winchester cartridge. The company necked its .458 Winchester case (from 1956) to accept 0.338-inch bullets and left a relatively straight case body and a 25-degree shoulder. Like the .458, the new .338 Winchester Magnum was suitable for use in .30-06-length actions, making rifles more affordable.
The outcome was a powerhouse that vastly outperformed any commercial round that had previously served the medium-caliber segment. The 1960 Winchester catalog lists two .338 Win. Mag. loads: a 200-grain Power-Point at 3,000 fps and a 250-grain Silvertip at 2,700 fps. Both produced just over 4,000 ft-lbs of muzzle energy.
That placed the new Magnum directly between the .375 H&H and the .300 Weatherby. Those numbers have come down a little today, and current voluntary velocity guidelines corresponding to the two original loads are 2,940 fps and 2,645 fps respectively.
The 250-grain version was conceived as the load for North America’s dangerous game: big bear species. Winchester even added an evocative name to the Model 70 variant it chambered for the .338: the “Alaskan.” The 200-grain load was for large non-dangerous species like elk, caribou, and moose. It proved to be a very effective tool in North America and also on the African plains.
Current ammunition selection and historical component bullet sales paint a different picture than I believe Winchester envisioned in 1958. Today, some companies no longer sell any 250-grain .338 Win. Mag. loads. Factory ammunition is dominated by 180- to 225-grain bullets. Some of this can be attributed to the newer ultra-premium bullets we enjoy today. Their tough construction can match or exceed the penetration of conventional bullets weighing much more.
This trend to lighter bullets in the .338 Win. Mag. already existed by the time I got to Speer in 1987, long before today’s high-tech projectiles were developed. Speer’s 200-grain 0.338-inch Spitzer Hot-Cor component bullet outsold our 250- and 275-grain bullets by a healthy margin. The superb Nosler 210-grain Partition was hugely popular. I’ve talked to very few handloaders who did not have that Nosler bullet in their arsenal.
The greater use of lighter bullets certainly implied the .338 Win. Mag. was being employed more on the big deer species than originally expected, but it should come as no surprise. The cartridge offers a decently flat trajectory, and its lighter bullets give excellent penetration, even on raking shots. I have talked to a lot of handloaders who bought a .338 Win. Mag. for bears but found it easy to handle if they downloaded 200- to 210-grain bullets to about 2,700 fps for deer.
Handloading data provides an interesting insight into the efficacy of the .338 Win. Mag.’s design. In 1956 the slowest-burning commercial canister propellant was H4831. If we look to the Hodgdon Data Center (hodgdonreloading.com), which is one of my favorite online resources, the data for many of the newer propellants indicate the new fuels don’t add much to what older propellants still accomplish in that cartridge. H4831 remains strong, and with 200- and 225- grain bullets, IMR 4350 and even 4895 can still produce top velocities. IMR 4350 drives bullets about as well as any slow-burning powder but with less propellant, and that’s handy when powder prices are high. To me this demonstrates the .338 Win. Mag. case configuration was close to optimal from the start.
When the .338 Win. Mag. was introduced, there were almost no component bullets. Those that were available were flatpoint designs with thin jackets for .33 Win. lever rifles with their tubular magazines and modest velocities. Although initial component offerings were few, they were all robust modern designs engineered for the .338 Win. Mag.’s capabilities.
There were a few “reboots.” Speer once made limited runs of a 0.333-inch 275-grain semi-Spitzer for a wildcat called the .333 OKH, a fine cartridge that Elmer Keith touted in print but one with only a niche market. As procedures to make the 0.333-inch bullets already existed, it was easy to make a new final form die to produce the same style in 0.338-inch diameter. It sold reasonably well to .338 Win. Mag. shooters who could expect 2,540 to 2,600 fps from safe handloads but was ultimately dropped to make room for new Speer bullets.
Today, many 0.338-inch bullets weighing over 250 grains are long-range match bullets. However, Hornady has a 285-grain ELD-X hunting bullet, and Nosler has two heavy AccuBond entries at 265 and 300 grains. These tough, modern heavyweights should provide enough penetration to deal with the largest thin-skinned game.
A reminder to handloaders: Make sure you inspect every fired case for signs of incipient case head separations. Use a straightened paper clip with a little right-angle jog at one end to probe the inside of the case wall ahead of the web. “Incips” can appear after only one or two firings with too many belted magnums, and the .338 Win. Mag. is no exception.
I’ve always admired .338-caliber cartridges because they cover a lot of useful tasks. Were I to buy a new .33-caliber rifle today, I’d have to go with one of the non-belted alternatives, probably the 33 Nosler. However, were I offered a nice old .338 Win. Mag. rifle that tickled my fancy, I’d make it work.