.300 Winchester Magnum

57 Years and Still Going Strong

- Brian Pearce

The .300 Winchester Magnum is currently enjoying greater popularity than at any time in its 57 year history, and in spite of many newer, excellent .30-caliber magnums appearing, it remains the most popular of all. It was originally conceived as a modern hunting cartridge suitable for taking all North American big game including moose and brown bear, but it also offers a flat enough trajectory and downrange power to hunt in open and mountainous country where long shots are common. In addition to widespread acceptance among hunters, it has proven a worthy long-range match cartridge. The U.S. government even adopted the .300 Winchester for use in the M24 Sniper Weapons System and Mk.13s rifles. There is a wide selection of components readily available that permit handloaders to fully duplicate and often exceed factory load performance.

The history of commercial .30-caliber magnum cartridges developed prior to the .300 Winchester is noteworthy and helps explain the design features of that cartridge. The .30 Newton, developed in 1913 and based on the German 11.2x72 Schuler case, is generally considered the first .30 caliber with magnum type performance, but its success was limited. The .300 Holland & Holland (H&H) Magnum appeared in 1925 (known then as the Super-Thirty) and was based on the .375 H&H Magnum belted case.

There are minor technical variances between the .300 H&H and the .30 Super Belted Rimless H&H cartridges, but they are not pertinent here. However, it should be noted that .300 H&H ammunition should not be fired in a .30 Super rifle, but the latter can be fired in the former.