In cooperation with rifle makers Browning and US Repeating Arms, Winchester Ammunition has developed a 30-caliber cartridge that delivers 300 Winchester magnum performance, yet can be used in a short action rifle.

The new beltless magnum is called the 300 Winchester Short Magnum or 300 WSM. The shell case of the new round is a new development by Winchester/Browning and is not based on any pre-existing case.

Benchrest rifle shooters who look for ultimate accuracy have been shooting the short, fat cartridge design for years. Short, fat cartridges like the 6mm PPC have developed a reputation for superb accuracy. The short action design of the 300 WSM cartridge also delivers excellent accuracy, even in a lightweight rifle. In addition, the beltless magnum design of the 300 WSM provides precise head spacing and reliable feeding.

The 300 WSM will be available in both the Winchester Supreme and Super-X lines of rifle ammunition. The reliable 180-grain Power-Point bullet will be loaded into the 300 WSM in the Super-X brand. This load will have a muzzle velocity of 2970 fps and muzzle energy of 3526 ft-lbs. This will be a good load for deer and medium-sized game.

Two loads in the 300 WSM will be available in the Supreme brand. The tough 180-grain Fail Safe bullet will be used with a muzzle velocity of 2970 fps and muzzle energy of 3526 ft-lbs. This will be an excellent load for elk, caribou, moose, bear and large deer.

Rounding out the offerings from Winchester is the aerodynamic 150-grain Ballistic Silvertip load that has an impressive muzzle velocity of 3300 fps. This flat-shooting load has a muzzle energy level of 3628 ft-lbs. When zeroed at 200 yards, the 150-grain BST bullet drops only 5.4 inches at 300 yards and retains over 1600 ft-lbs. of energy at 500 yards. For long-range shooting on deer and antelope size game, this load will be hard to beat.

Both Browning and U.S. Repeating Arms Company have chambered the new 300 WSM in two of their rifle models — Browning's A-Bolt and U.S. Repeating Arms Company's Winchester Model 70. The A-bolt is available in four configurations and the Model 70 in three. Pictured below A-Bolt (left) and the Model 70.