The Winchester Model 1912 (also commonly known as the Model 12, or M12) is an internal-hammer, pump-action, shotgun with an external tube magazine. Popularly named the Perfect Repeater at its introduction, it largely set the standard for pump action shotguns over its 51-year high-rate production life. From August 1912 until first discontinued by Winchester in May 1964, nearly two million Model 12 shotguns were produced in various grades and barrel lengths. Initially chambered for 20 gauge only, the 12 and 16 gauge versions came out in 1913 (first listed in the 1914 catalogs), and the 28 gauge version came out in 1934. A .410 version was never produced; instead, a scaled-down version of the Model 12 known as the Model 42, directly derived from scaled drawings of the Model 12, was produced in .410.