The Benelli M4 Tactical Shotgun is a semi-automatic, tubular magazine fed weapon chambered for the 12 gauge (18.4 mm) shotshell cartridge. The operating system employed in this weapon is the improved ARGO (Auto-Regulating Gas Operated) Twin (two gas pistons/cylinders/ ports) System with rotating bolt head with dual locking lugs. The Benelli Armi S.p.A. line of semi-automatic M4 shotguns is a result of painstaking work at Benelli's Research and Development Center and of Benelli's extensive experience in precision engineering and technical know-how. A number of military and police forces, domestic and foreign, have chosen the M4 special version to be used where the greatest reliability of service in required. The small number of components, an extremely simple operating principle, make the new shotguns highly reliable and practical, easy to strip and upkeep to the extent that the M4 can be considered are of the most modern, accurate, safe and fast shotgun available today. ...