300 Winchester Magnum Evolution, History, and Performance

by Ron Spomer

Winchester had a better idea in 1963 and it has lasted for nearly 60 years. The 300 Winchester Magnum.

Thirty caliber magnums were nothing new in 1963. Holland and Holland necked down their 375 H&H magnum to make the 300 H&H Magnum in 1925. Roy Weatherby hot rodded it to make his 300 Weatherby Magnum in 1944, adding a whopping 400 fps to the H&H’s speed. Norma over in Sweden even announced its 308 Norma Magnum in 1960, another modification of the H&H belted case.

So why did Winchester even bother showing up for this party so late in 1963? Because of the 7mm Remington Magnum, I suspect.

In 1962 the 7mm Remington Magnum became the must have cartridge, prompting Winchester to get hopping on development of its 300 Winchester Magnum. Both are standard-length action modifications of the 300 H&H Magnum case.

After Remington released its standard-length, belted 7mm magnum in its new, accurate, budget priced Model 700 rifle in 1962, Winchester was practically on the canvas. It’s competing 264 Win. Mag. was no longer so competitive. The 7mm threw deer and elk-sized bullets just as fast if not faster and went well beyond the 140-grain bullets typically loaded in the 264 magnum. The larger bore didn’t burn out as fast as the throat of the 264, either.

Well, by golly, this was America, land of the 30-30 and 30-06. If Remington could titillate the masses with a silly 7mm cartridge, Winchester could blow their skirts over their ears with an even more powerful 30-caliber magnum. But how to do it?

Weatherby had already maximized the 300 H&H case in full magnum length. Norma had necked down Winchester’s own shorter, standard-length action 338 Win. Mag. case. What was left?

More powder space in a standard length case. Winchester shoved the shoulder forward as far as they dared, leaving just a .264-inch long neck to secure their 150-, 180-, 200-, and 220-grain bullets. That created a reservoir large enough to harbor some 83 grain of water, Dry it out and you had room for more powder than the Norma or H&H could hold. And you had it in a case that would fit common, relatively affordable American rifles like Winchester M70.

Winchester’s Model 70, The Rifleman’s Rifle, was a ready platform for the 300 Winchester Magnum. The 264 Win. Mag for which it was already chambered was fading fast under the onslaught of the 7mm Rem. Mag. All Winchester had to do was replace the 264 barrels with 300 barrels.

Winchester didn’t have a hit with the 300 Winchester Magnum. It had a grand slam home run. But not on the first pitch. It took a few years for the buzz to catch up to the 300’s velocity. But once shooters realized they could fire the 300 without follow up shoulder surgery and knock elk, moose, grizzlies, and brown bear over in the process, the bandwagon filled. Everyone was tooting the 300 Winchester Magnum’s horn.

And why not. A 180-grain bullet at nearly 3,000 fps sent 3,600 foot-pounds of energy flying. A 150-grain at 3,400 fps carried point blank range for a six-inch target out to 330 yards. And, despite being the lightweight in the family, this little slug carried more than 1,700 f-p energy at 500 yards! Deer and elk didn’t stand a chance.

The world’s biggest deer and antelope, like this eland bull, were no match for the 300 Winchester Magnum. They still aren’t. The Rifle is an Empire Rifles Mauser, Leupold VX 3 scope. Jamy Traut led me to this ancient, worn-down bull in Namibia.

Predictably, the 300 Win. Mag. became the darling of the big game hunting world, sportsmen toting it to the Rockies, the Alaska Range, the Yukon flats, the Australian Outback, the African Plains. Brown bears, polar bears, water buffalo, rhino, hippo, Cape buffalo, even elephants began succumbing to the caress of the 300 Winchester Magnum.

Not everyone loved paying the price for this performance. The 300 earned a reputation as a kicker. But no red blooded American hunter was going to admit he couldn’t handle the new American 30-caliber King. From cousin Todd to Uncle Albert, anyone heading West for elk, moose, or bears was doing it with a shiny new 300 Win. Mag. under his wing.

Once one of the fastest 30s, the 300 Winchester Magnum now rests in the middle ground between the old 30-06 and radical monster 30s like the 300 RUM.

These days the eruption of such monsters as the 300 Remington Ultra Magnum, 30 Nosler, and 30-378 Weatherby Magnum put a shade over the 300 Winchester Magnum, but not much of one. New bullets and new powders keep the old Win. in the ring, ducking and bobbing and flashing out with the kind of high velocity punches that make it as relevant today as it was when the Beatles wanted to Hold Your Hand. It still fits standard length actions, still shoots fast and hard, still handles any game on the planet. And burns a lot less nitro then it’s oversized cousins.

If you’re looking for a universal, do-all, world beater cartridge, you’re looking for a 300 Winchester Magnum. One of the best and most enduring inventions to come out of the 1960s.

The 300 Winchester Magnum is more versatile than even the 30-06 because it can be handloaded with the same bullets, but pushed a lot faster.

300 Win. Mag., 150-grain Barnes TTSX

300 Win. Mag., 180-gr. Nosler AccuBond

300 Win. Mag. 212-grain, Hornady ELD-X

7mm Rem Mag., 140-grain Nosler AccuBond

30-06, 180-grain Nosler AccuBond

# # #