The Benelli M4 Tactical shotgun is a unique, Auto-Regulating Gas-Operated (A.R.G.O.) semi-auto. The M4 Tactical is the combat service shotgun of the U.S. Joint Services today. Originally designed in 1998 for the U.S. Marine Corps, the M4 (M1014) was extensively tested at the Aberdeen Proving Ground in Maryland. It proved totally reliable for safety, function, and performance. This model features Benelli's H2O titanium cerakote finish for great corrosion resistance.