.458 Winchester Magnum

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The .458 Winchester Magnum is a rifle cartridge. It was introduced by Winchester in 1956. The cartridge case is based on the .375 H&H case cut off to 2.5 in (64 mm), and blown out to accept a .458 cal (11.6 mm) bullet. With good handloads one can expect approximately 2170 feet per second (660 m/s) with 500 grain (32.4 g) bullets (achieved using a barrel of 24 inches (610 mm)).

Winchester no longer sells ammunition in .458 Winchester Magnum, but other manufacturers do. Hornady offers what they call a "heavy magnum" loading that features a 500 gr (32.4 g) bullet with a velocity of approx 2250 feet per second (690 m/s). They use a special powder available only to them, and not the reloader. Numerous different gun companies offer rifles in this caliber, including the model 70 Winchester. It can be loaded down using bullets as small as 350 grains (22.7 g).

The cost of these rounds are prohibitive, leading to a high number of handloaded cartridges. The recoil of the factory loads is about 70 foot pounds. Handloads can be made that will make this cartridge more confortable to shoot.

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