The Winchester Model 12, more formerly known as the Winchester Model 1912 (also commonly referred to as the M12 or Model 12) is a pump action or hammerless slide-action, shotgun with an external tube magazine.
Nicknamed, the Perfect Repeater at its introduction, this shotgun se tthe standard for pump action shotguns throughout its fifty one (51) year high rate manufacture and production life. From 1912 until the shotgun was first discontinued by Winchester in 1963, nearly two million Model 12 shotguns were manufactured and produced in various barrel lengths and grades. Initially the M12 was chambered strictly for 20 gauge, however 12 and 16 gauge versions came out in or around 1914, and the 28 gauge version of the Winchester Model 12 came out in 1934. A .410 version was never produced; instead, a stripped down variatn of the Model 12, commonly known as the Model 42, was derived directly from scaled drawings of the model 12 and produced instead.