Introduced in 1963, the .300 Winchester Magnum was the last of Winchester’s family of standard-length belted magnums, following the .458 Winchester Magnum (1956) and the .264 and .338 Winchester Magnums (1958). All were based on the .375 H&H case, shortened to (more or less) .30-06 length and necked to caliber. The .300 Winchester Magnum would become the most popular of all. In fact, it is the world’s second-most popular belted magnum, following the 7mm Remington Magnum. There may even come a time when it surpasses Remington’s “Big Seven” in popularity. Current indications are the 7mm is slipping a bit in sales, while, despite all the other fast .30s out there, the .300 Winchester Magnum seems to just keep rolling along, a true world standard of a hunting cartridge.
That sounds complimentary, and is-and is deserved. However, I should probably say that I have never particularly liked the .300 Winchester Magnum. Sorry, nobody can love all cartridges equally! It was intended to be a modernized replacement for the aging .300 H&H, which has an archaic tapered case and required a full-length (.375 H&H-length) cartridge. This was successful; within 20 years it nearly erased the .300 H&H-but I’m still a fan of the old warhorse. Grudgingly, however, I will certainly admit that the .300 Winchester Magnum is a bit faster, even with its shorter case.
The .300 Winchester Magnum is not as fast as the .300 Weatherby Magnum, which preceded it by nearly 20 years. I’m also a fan of the .300 Weatherby, although I concede that its requirement for a full-length action and its unquestionably greater recoil are drawbacks. However, I tend to the think the reason the .300 Winchester Magnum is much more popular than the faster .300 Weatherby is simply because it has been offered by many more manufacturers.
There are other magnum .30-calibers that are faster yet, with the same drawbacks of larger cases and more recoil. There are also several new .30-caliber short magnums, including the .300 WSM, .300 RSAUM, and .300 RCM. All of these offer unquestionably better and more modern case design; they are all unbelted, with shorter, fatter, more efficient cases. All three offer performance that is “similar” the .300 Winchester Magnum-which is very good indeed from their more compact cases. Despite all the hype, however, none of them are actually quite as fast as the .300 Winchester Magnum, especially with heavier bullets… and regardless of performance, it is unlikely that any of these newcomers will ever surpass the .300 Winchester Magnum in popularity and availability!
Today’s factory loads vary considerably in velocity, with “extra fast” loads like Federal’s High Energy and Hornady’s Superformance sort of breaking the paradigms of what we expect from our cartridges. However, the .300 Winchester Magnum is sort of “standard” with a 150-grain bullet at about 3200 fps and a 180-grain bullet just shy of 3000 fps. Its detractors (sometimes including me) will quickly point out that this is not as fast and thus not as flat-shooting as several other .30-caliber magnums, and this is true. However, it is plenty fast enough to make the .300 Winchester Magnum a wonderfully versatile cartridge, not just in terms of its ranging abilities, but also in terms of the energy it carries, and thus its suitability for a very wide range of game.
The .300 Winchester Magnum is, for example, a better mountain cartridge than the .30-06 because it shoots much flatter. It is also a better cartridge for larger game such as elk, because it hits harder! On the other hand, and this is important, recoil is not nearly as brutal as it is with the faster .30s.
One of the long-standing principles of cartridge design is that a cartridge should have a case neck at least equal to the diameter of its bullet. Supposedly this is required to allow the case a proper “grip” on the bullet, which is conducive to accuracy. So a .30-caliber cartridge should have a case neck of at least .308-inch in length. The .300 Winchester Magnum breaks this rule. It has a very short neck, which allows larger powder capacity and gave it higher velocities-especially with the powders available back in 1963. Detractors of the cartridge have long argued that it cannot be especially accurate because of this “design flaw.”
I have never joined that group. Theoretically they are probably correct, but this business about a “caliber-length neck” must not be one of the most important contributors to accuracy. The .300 Winchester Magnum has never been considered an ideal benchrest cartridge, but it can be and often is extremely accurate. It has been used successfully in long-range competition, and is currently being used as a sniper rifle by some units, including the U.S. Navy SEALs. So much for accuracy except to add that, over the years, I have used many test rifles in .300 Winchester Magnum-and owned several rifles in this chambering-that were spectacularly accurate.
Although it isn’t my personal favorite, I have actually used and hunted with the cartridge quite a bit, and in lot of places for a significant variety of game. The .300 Winchester Magnum has never let me down! It is truly versatile and hard-hitting, with clear-cut advantages of tremendous availability and acceptable recoil. Given a choice, I might choose a different cartridge for myself. But when other shooters ask for recommendations on a hard-hitting, flat-shooting cartridge they can use for a wide variety of hunting-especially if they don’t handload-I can’t think of a more sensible choice than the .300 Winchester Magnum.