The .357 S&W Magnum (9x33mmR), or simply .357 Magnum, is a revolver cartridge created by Elmer Keith, Phillip B. Sharpe,[5] and Colonel D. B. Wesson[5] of firearms manufacturer Smith & Wesson, and Winchester.[6][7] It is based upon Smith & Wesson's earlier .38 Special cartridge. The .357 Magnum cartridge was introduced in 1934, and its use has since become widespread. This cartridge started the "Magnum" era of handgun ammunition.[8] The .357 Magnum cartridge has a positive reputation for stopping power.