The M4 Super 90 is an Italian-developed and made shotgun manufactured by Benelli Armi S.P.A.On May 4, 1998, the U.S. Army Armaments Research, Development and Engineering Center (ARDEC) at Picatinny Arsenal, NJ issued requested submissions for a new 12 gauge, semi-automatic combat shotgun for the US Armed Services. In response to the request, Benelli Armi S.P.A. of Urbino, Italy designed and built the Benelli M4 Super 90 Combat Shotgun. On the 4th of August, 1998, five samples of the M4 were delivered to Aberdeen Proving Ground, Maryland for testing. After intense testing, the Benelli M4 beat the competition. In early 1999, the U. S. Army ARDEC awarded the M1014 Joint Service Combat Shotgun contract to Beretta USA Inc. for importation of the Benelli M4 Combat Shotgun. The first units (count of 20,000) were delivered to the US Marine Corps in 1999.The M4 was the first gas-operated shotgun produced by Benelli. Its function is designed around an entirely new method called the \"auto regulating gas operated\" (ARGO) system. The design uses 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. It is also self-regulating for cartridges of varying length and power levels. It can fire 2.75 and 3 inch 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 accessory rail on top allows use of both conventional and night-vision sights, while retaining use of the original sights.