.458 Winchester Magnum

Winchester introduced this cartridge in 1956 to let a bolt-action rifle reach the performance class that had, until then, belonged to expensive imported double rifles built for African dangerous-game hunting. Necked up from the belted .375 H&H Magnum case and shortened to fit a standard long action, it was first chambered in the Winchester Model 70 African, a rifle aimed squarely at the hunter who could not justify a bespoke double.

The round’s reputation suffered a setback around 1970 that had nothing to do with its design. Some factory loads of the period were assembled inconsistently and gave erratic velocities, which put the cartridge’s performance on dangerous game in question for years after the loading was corrected.

Its dimensions are set by C.I.P. rather than by the American SAAMI body that governs most other American sporting cartridges, and every figure recorded here comes from that C.I.P. standard. The four bullet weights and types listed are drawn from a handloading data sheet; that sheet’s velocities are maximum-load results specific to a particular powder charge rather than facts about the cartridge itself, so no velocity is recorded for any of them.