300 win mag
The .300 Win Magn was, and is, a solid success. For the insane, and those who are mesmerized by very high initial velocities with light bullets (often the same people), it moves 150-grain slugs at 3,200 fps and more and 165s at 3,100 plus. But it’s the 180-grain bullets, at a solid 3,000 fps or just under, that do the real heavy lifting.
The .300 Win Mag is a big-game cartridge, not a deer and antelope cartridge, and here you have enough bullet weight to do the job on hefty critters combined with a very flat trajectory.
And there’s more. This .300 Win Mag will really shoot. For all its power, it’s capable of uncanny accuracy.
In the past, I have chided the .300 Win Mag for what it isn’t. Compared to the big .30s by Weatherby, Remington, and others, for example, it isn’t much of a magnum. Compared to the .30/06, it isn’t much more capable on game. But there’s another way of looking at it: What the .300 Win Mag isn’t—overly powerful, too hard-kicking, terribly expensive—goes a long way toward explaining what it is: one of the most popular and useful magnums around.
In 1962 Remington introduced its weak-kneed and flaccid* 7mm Remington Magnum. Since only eight people in the United States who did not work for a gun company had chronographs, and since the things were such a pain in the ass to use that only four of those eight actually consulted them, the new cartridge became a raging success.
Winchester, stung by the failure of its .264 Winchester Magnum, felt obliged to do something. And they did. But rather than bring out a competitive 7mm mag, they turned to the .30 magnums.
Despite the success of the .300 Weatherby, Winchester designed a cartridge with considerably less power. Their reasoning was sound. While the Weatherby’s ballistics were spectacular, so was its recoil and the cost of the ammo. It also required a magnum-length action.
So, the new .300 Winchester Magnum was based on a short-necked case that would work through a .30/06-length action and would push a 180-grain bullet at a real-world 2,950 fps, while the Weatherby shot the same slug at 3,150. The smaller case cut down on cost while the lesser powder charge reduced the recoil and muzzle blast.