The Smith & Wesson Model 27 is the first revolver designed to fire the .357 Magnum cartridge. It was introduced in 1935 and was originally called the Registered Magnum.
Built with a six-round cylinder, the Model 27 was offered in a series of custom-built barrel lengths between 3.5 inches and 8.75 inches. Although initially introduced as a civilian firearm, the Registered Magnum proved popular with law enforcement. The .357 Magnum cartridge has proven to be among the most popular types of handgun ammunition. It is renowned for its stopping power and is favored by big game hunters. General George S. Patton was an early proponent of the gun.