Benelli M4 The Benelli M4 Super 90 is an Italian semi - automatic shotgun manufactured by Benelli Armi SpA . History . On May 4 , 1998 , the United States Army ' s Armaments Research , Development and Engineering Center ( ARDEC ) at Picatinny Arsenal , New Jersey issued Solicitation # DAAE30 - 98 - R - 0401 , requesting submissions for a new 12 gauge , semi - automatic combat shotgun for the U . S . military . In response to the request , Benelli Armi SpA of Urbino , Italy designed and built the Benelli M4 Super 90 Combat Shotgun . On August 4 , 1998 , five samples of the M4 were delivered to Aberdeen Proving Ground , Maryland , and after intense testing , the M4 had beaten the competition . In early 1999 , ARDEC awarded the M1014 Joint Service Combat Shotgun contract to Heckler & Koch , American 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 named " XM1014 " , but after adoption , the ' X ' was dropped , and the weapon was officially designated the " M1014 " . Design . 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 ARGO system on the M4 opened the door for Benelli ' s development of the R1 rifle line . The design uses two stainless - steel self - cleaning piston s 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 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 . Serviceability . Also touted is the modular assembly basis of the weapon . It allows an operator to exchange the various assembly groups ( barrel , buttstock , forearm , etc . . . ) without the use of tools . Especially useful in the field , the process is quick and allows the weapon to adapt to a changing tactical environment . Durability . Preliminary testing of the M4 puts its reliability at the top of the scale . It can reliably function for at least 25 , 000 rounds without replacement of any major parts . The steel components of the weapon feature a matte black phosphated corrosion resistant finish while the aluminum parts are matte hard - anodized . These finishes reduce the weapon ' s visibility during night operations . The weapon requires little maintenance and operates in all climates and weather conditions . Collapsible buttstock . The buttstock is collapsible on the M4 Model ( designated 11707 ) but will not collapse on the M1014 . This is because the M1014 was manufactured before the U . S . 1994 assault weapon ban expired , whereas the M11707 has been manufactured since the ban expired therefore not subject to the terms under the ban . Collapsing the buttstock shortens the weapon by almost 8 inches , allowing easier storage and transportation ; furthermore , it permits better maneuverability around tight corners and over obstacles . The M4 is also available with a fixed stock ( pistol grip and semi - pistol grip styles are both available ) . The M4 is no longer sold today with the skeleton fixed stock ( model M11707 ) to civilians . Benelli only sells the M4 with a fixed pistol grip style tactical stock in the United States . However , the collapsible butt stock can be purchased by civilians in Canada . Rail interface system . The rail interface system or Picatinny rail , built into the top of the shotgun accepts scopes , laser illuminators , night - vision sights , and flashlights . Most modern military firearm s have similar structures . Benelli Tactical and the M4 . Benelli Tactical is a division of Beretta ' s Law Enforcement ( LE ) division . Benelli Tactical manages the sales of all Benelli tactical shotguns to law enforcement , government , and military entities . The M4 shotgun is sold in three configurations : M4 Entry with a 14 in barrel ; M4 with a 18 . 5 in barrel ; and M1014 , which is an M4 with the " M1014 " nomenclature on it for military usage only . M4 shotguns sold through Benelli tactical are available with the collapsible buttstock . Benelli Tactical and Beretta LE have maintained the belief that the collapsible buttstock , while no longer illegal in the United States , is still only to be made available to law enforcement and government agencies . Benelli Tactical / Beretta LE will not sell these stocks to private individuals . Benelli Tactical does sell the stock piece for retrofitting the pistol grip stock for $ 150 . The stock must be direct - shipped from Italy , however it and other aftermarket stocks are commercially available and not restricted by the United States . Suggested retail price of the civilian version is around $ 1 , 899 . An NFA stamp is required to purchase or own the 14 . 5 " barreled model only since this model is considered to be a Short Barreled Shotgun or SBS . Standard magazine capacity of the civilian version is 5 + 1 , although it is possible to fit 6 + 1 and two shot extension tubes are sold by Benelli as well as some other companies . Some LE models have become available to private individuals on the secondary market .