In 2001, Winchester and Browning collaborated to introduce Rick Jamison’s .30 caliber wildcat magnum, which was branded the .300 Winchester Short Magnum or WSM (sometimes pronounced “wizzum”).

By design, it duplicated the ballistics of the renowned .300 Winchester Magnum, which has been with us since 1963, itself having been billed as a “short magnum.” Like many others, I raised an eyebrow and said aloud, “Why the bleep do we need another .300 Winchester Magnum? What’s wrong with the old one?”

Apparently, those who took the chance on this “newer, ‘shorter’ short magnum” saw some things myself and many others had overlooked. First off, in an apples to apples comparison, the .300 WSM and .300 Win Mag loaded with factory ammunition ARE equals. Of course, with handloads the .300 Win Mag will outrun the WSM as it has a larger case capacity. The more efficient case design and innovations in modern smokeless powder enable the WSM to do more with less.

Secondly, as the WSM case utilizes a cartridge overall length of 2.860 inches it can be housed in a short action, whereas the .300 Win Mag needs a long action due to its 3.340-inch overall cartridge length. Shorter actions make for a lighter rifle, and lighter rifles are much less laborious to parade around in the mountains.

But hey, won’t a lighter .300 Magnum kick the daylights out of us, mister gun writer? For once in our lives, that part of the lunch is free. That WSM case design I mentioned before makes a shorter, wider powder column, which burns more efficiently than the longer, narrower one of the .300 Win Mag. And for that reason, perceived recoil is less. The same performance for less recoil? Where do we sign up?

If that is not enough, here is another amazing trait of the .300 WSM. In every other .30 caliber cartridge that I have ever used, whenever changing bullet weight or style, one must sight in to the new load. Not so with the .300 WSM. In more than one rifle thusly chambered, I have been able to switch from 150 grain factory loads to 180 grain handloads without any adjustments to the scope.

Recently I borrowed my father’s .300 WSM, a Model 70 Sporter, and repaired to the range with some 150 grain Corelokt Tipped factory ammunition to sight in for elk season. Even though it had been zeroed with 180 Accubond handloads, the first three shots on paper with the 150 grain ammunition printed dead center 1.5 inches high at 100 yards. That is useful.

Winchester also released the .270, 7mm and .325 WSM cartridges, as well as the .223, .243 and .25 Winchester Super Short Magnum (WSSM) cartridges, but the .300 WSM is far and away the most popular. And with good reason — it is a darn good cartridge.

While the rest of the WSM/WSSM cartridges dwindle on the edge of obscurity, the .300 continues to sell. Although factory ammunition usually weighs between 150-200 grains (the most useful range for hunters), the .300 WSM comes with a 1/10-inch twist and that allows handloaders to take advantage of the full range of bullet weights (100-220 grain) offered in .30 caliber.

Efficient, accurate and powerful, that’s the .300 WSM. If you’re in the market for .300 Magnum performance in a lighter-weight package and with less recoil, look no further — it is the real deal.

Are you a fan of the .300 WSM? Write to us at shootingthebreezebme@gmail.com today!