Benelli M4

The Benelli M4 is an Italian semi-automatic shotgun manufactured by Benelli Armi SpA.

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. Additionally, the weapon is self-regulating for use with cartridges of varying length and power levels. It can fire 2.75 (70 mm) 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. A Picatinny sight rail on top allows use of both conventional and night-vision sights, while retaining use of the original sights.

The modular basis of the shotgun means many of its features can be reconfigured as needed. It allows a user to quickly exchange the various assembly groups (barrel, buttstock, forearm, etc.) without the use of tools.