shotgun manufactured by Benelli Armi S.P.A. The history of the M4 begins on May 4, 1998, where the U.S. Army Armaments Research, Development and Engineering Center at Picatinny Arsenal requested submissions for a new 12 gauge, semi-automatic combat shotgun for the US Armed Services. Benelli Armi SpA of Urbino, Italy responded by designing and building the Benelli M4 Super 90 Combat Shotgun. On August 4, 1998, five samples of the M4 were delivered to Aberdeen Proving Ground in Maryland, and after intense testing, the M4 beat all other weapons that were entered. In early 1999, ARDEC awarded the M1014 Joint Service Combat Shotgun contract to Heckler & Koch, USA subsidiary for importation of the Benelli M4 Combat Shotgun. The first units (count of 20,000) were delivered to the United States Marine Corps in 1999. During testing, the prototype was called the XM1014, but after adoption, the ‘X’ was dropped, and the weapon was officially designated the M1014. The M4 was the first gas-operated shotgun and its function is designed around an entirely new method called the “auto regulating gas operated” (ARGO) system. The ARGO system on the M4 opened the door for Benelli’s development of the R1 rifle line. The design contains two stainless-steel self-cleaning pistons located just ahead of the chamber to function opposite the rotating bolt, thereby eliminating the need for the complex mechanisms found on other gas-actuated automatics. Benelli accomplishes this level of reliability through the
simplicity of the mechanism. The ARGO is a short-stroke system that incorporates only four parts. It consists of two symmetrical shrouds containing two small steel gas pistons. It is also self-regulating for cartridges of varying length and power levels. It can fire 2.75 and 3-inch (76 mm) shells of differing power-levels without any operator adjustments and in any combination. Low-power rounds, such as less-lethal rubber pellets, must be cycled manually. The sights are military-style ghost ring and are adjustable in the field using only a cartridge rim. The MIL-STD-1913 Picatinny sight rail on top allows use of both conventional and night-vision sights, while retaining use of the original sights.