The .357 Magnum was introduced in 1935 as a joint effort between Smith & Wesson and Winchester. It was the first magnum revolver cartridge that enjoyed widespread popularity. It has been chambered in a variety of double-and single-action revolvers, single-shot pistols, autoloading pistols, derringers and many rifles. It has proven useful for hunting, target work, defense and law enforcement and is a versatile revolver cartridge. Original loads were advertised to push a 158-grain cast, SWC-style bullet faster than 1,500 fps from an 8¾- inch revolver barrel with vintage factory loads containing 15.3 to 15.4 grains of Hercules 2400 powder. Although several fast-to medium-burn rate powders produced excellent accuracy, velocities were comparatively low. For top performance, Alliant 2400, Accurate No. 9 Hodgdon H-110 and Winchester 296 are good choices.

Although the accompanying data was tested with CCI 550 Small Pistol Magnum primers, all data can be fired with CCI 500 Small Pistol standard primers. Exceptions include loads containing Hodgdon H-110 and Winchester 296, which should be used with a magnum primer to assure reliable ignition.

A heavy crimp is advised to aid in achieving correct powder ignition and to prevent bullets from jumping crimp when subjected to recoil. Industry maximum average pressure for the .357 Magnum is currently established at 35,000 Psi. It is noteworthy to mention that early ammunition was loaded to and industry maximum average pressure of 46,000 CUP. Those pressure guidelines were reduced to prevent problems that surfaced in certain guns when subjected to a steady diet of heavy loads.

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