During more than 150 years of firearms and ammunition innovation, Winchester has created veritable icons, products that define their categories. Like the Model 94 lever action, the .243 Winchester cartridge, the Model 12 pump-action shotgun, and the Model 70 bolt-action rifle. But of all Winchester products, none is arguably more useful, versatile, long-lived, effective, and impressive than the .300 Winchester Magnum.
Certainly the .30-30 Winchester has accounted for more game and sold more copies. The .270 Winchester is more unique. But for all-round performance and versatility, it’s hard to beat the .300 Win. Mag.
The .300 Win. Mag., of course, fires bullets .308-inches in diameter—the famous .30-caliber. There is nothing magical about this bullet diameter other than that it strikes a good balance between big enough and too big. Bullets that are too large in caliber need to be long and heavy to be ballistically efficient. That requires a lot of powder to push; this increases recoil and/or gun weight. Bullets that are too small in caliber reduce recoil and/or gun weight, but may not have sufficient mass and downrange energy for maximum tissue destruction.
Winchester’s .30-30, originally released in 1895 as the .30 Winchester Center Fire, introduced both smokeless powder and the .30 caliber to a mass audience. There had been a rather obscure .30-30 Wesson black-powder cartridge around 1880, but the then all-new Winchester .30-30 is what put the .308 bullet on the map as America’s deer hunting standard.
The U.S. military then chose the .30-caliber .30-06 Springfield as the right balance shortly after the Spanish American war of 1898 introduced us to the deadly M1893 Mauser bolt action. That fast-loading rifle fired the “Spanish Hornet,” the 7x57mm Mauser cartridge. The .30-06 case is essentially an elongated modification of the 7x57mm. The bolt-action Model 1903 Springfield service rifle had so much in common with the Mauser M98 that Mauser Werke sued and the U.S. had to pay it $250,000 in royalties.
During WWI and WWII the .30-06 Springfield and M1 Garand introduced millions of Americans to the .30-06 cartridge. It proved as effective on 200-pound deer as 200-pound enemy soldiers, and by mid-century big-game hunters like Theodore Roosevelt, Ernest Hemingway, and Stewart Edward White had proven it deadly on everything from kudu and rhino to lions and buffalo. The .30-caliber mystique continued to grow.
Not to be upstaged by their American cousins, the British reshaped their .375 H&H belted magnum to .30 caliber and released it as the Holland Super .300, soon to be better recognized as the .300 H&H Magnum. It outmuscled the .30-06 by about 200 feet per second. The arms race was on.
Roy Weatherby actually leaped ahead in that race with his .300 Weatherby Magnum in 1944. It bested the .300 H&H by about 400 fps, but it was rarely chambered in anything but expensive Weatherby rifles or customs.
Winchester didn’t hit the streets with its .300 magnum until 1963, almost two decades after the Weatherby appeared. To its credit, the company did not try to beat Weatherby’s speed record, even though it used the same basic .375 H&H belted-magnum case as the foundation for its new round. Instead, Winchester wisely shortened the case enough so that it would conveniently function through standard-length (.30-06 length) rifle magazines and actions.
To regain some of the lost powder capacity, they shoved the shoulder forward significantly. This left slightly less than a full caliber of neck for grabbing seated bullets. This is often criticized as a shortcoming, but I’ve never seen a .300 Win. Mag. cartridge that wouldn’t shoot accurately due to bullets getting bumped out of alignment.
The .300 Win. Mag’s resulting power reservoir (it holds 70 to 80 grains of most suitable powders) is enough to drive 180-grain bullets 3,000 to 3,160 fps from 24-inch barrels. That is 300 to 100 fps slower than the Weatherby, but 100 to 300 fps faster than the .300 H&H. And, because the Win. Mag. doesn’t require a magnum-length action, virtually every riflemaker chambers for it, even in some lever-action and autoloading rifles.
Free-recoil energy in an eight-pound rifle shooting full-power, 180-grain .300 Win. Mag. loads is about 28.62 foot-pounds, and the recoil velocity of that rifle is about 15.18 fps. Compare this to a .30-06 180-grain load in the same rifle; free-recoil energy is 22.4 foot-pounds and recoil velocity is 13.43 fps.
Free recoil from a .300 Wby. Mag. hits 31.52 foot-pounds and recoil velocity climbs to 15.93 fps. The .300 Win. Mag., then, generates about as much recoil as most shooters enjoy handling, which is a big part of why this is the most popular .300 magnum cartridge in the world—and will probably remain so.
At the other end, a sleek 180-grain bullet like Winchester’s Ballistic Silvertip or AccuBond CT will deliver more than 1,750 foot-pound of energy at 500 yards, more than the .30-30 delivers at 200 yards.
Finally, like the .30-06, the .300 Win. Mag. is capable of shooting bullet weights from 100-grain plinkers to 220-grain moose and bear thumpers. You’ll probably have to load your own at these extreme ends, but that’s the price you pay for the ultimate versatility from the world’s most popular, versatile, do-everything .300 magnum.