The M1 is a semi-automatic shotgun that uses an inertia driven system that is derived from the HK 512 mechanism. The M1 uses a metal receiver, smoothbore barrel and tubular magazine under the barrel. The fixed stock and forearm are made out of high strength polymer. Most tactical models are fitted with a pistol grip, although a conventional grip is available. Sights are either standard shotgun sights or ghost ring diopter sights. For civilian use the M1 is also available with longer barrels and in 20ga.
