This cartridge is a very good medium-bore cartridge that was introduced by Winchester, along with the .264 Magnum and the .458 Magnum, in about 1958.
They named the Model 70 rifle chambered for the .338 “The Alaskan, a pretty good indication of the type of game the Winchester developers figured it would be most useful on. It was pretty much and immediate success among Alaskan guides and residents alike.
The cartridge most likely had its origins in the efforts of three men in the late 1940s, experimenting with a couple similar cartridges. The men were Charles O'Neil, Elmer Keith, and Don Hopkins, and the cartridges were the .333 OKH and the .334 OKH.
The .333 OKH was based upon a .30-06 case necked up to a .33 caliber bullet, and the .334 OKH used a shortened .375 H&H case necked down for the same bullet. The .338 Winchester Magnum also used a shortened and blown-out .375 H&H case, necked down to accept a .338 caliber bullet.
Elmer used his .333 OKH as his second rifle on his first African Safari, and as I now recall it was a custom Mauser built by Montana rifle smith Iver Hendriksen. I vividly recall reading his descriptions of some of the difficulties he encountered using the cartridge.
He was using English made bullets and their performance on game was pretty dismal. The failures were in no way the fault of the cartridge, but rather the construction of the bullets. We are very fortunate these days to have plenty of really excellent bullets. Members of the Keith era were not so fortuitous.
I also recall reading in Keith's writings that the .333 OKH became the .338 Win magnum, and the .334 OKH, became the .340 Weatherby. I suspect that there is a lot of truth in those comments.
The .338 is an excellent cartridge for larger big game. It is a great elk rifle when hunting wapiti in heavy timber. It is as good as any cartridge on big moose (and eland in Africa), and it really shines on the big bears.
One well-respected outfitter in Alaska used to require his bear guides to carry a .338 chambered rifle when chasing the bruins. Whether that is till the case or not, I can say.
Ammunition is available loaded with an assortment of good bullets, weighing from 200 grains to 300 grains. For normal use in the field doing anything other than backing clients on big bears, bullets in the 225-250 grain range are perhaps the most useful.
There isn't much that a 225 grain quality bullet cruising along at about 2,800 fps won't handily take care of. It is a relatively high pressure cartridge with the SAAMI recommended average pressure at 64,000 psi, and the CIP a bit less at 62,000 psi.
In my hunting career, I have had but one occurrence where an animal decided to test my mettle by taking me on. It was an Alaskan brown bear, and I was armed with a custom pre-64 Model 70 chambered for the .338 Win. Mag. loaded with handloaded ammo using 210 grain Nosler partition bullets.
I won't get into the details, but since I'm writing these lines, needless to say, it worked.