The battle proven Benelli M4 Tactical is an auto-regulating gas-operated semi-automatic shotgun currently used as the combat service shotgun of the US Joint Services. Originally designed in 1998 for the US Marine Corps, the M4 Tactical features a picatinny rail for mounting scopes and ghost-ring sights for quick target acquisition. The shooter can easily replace various assemblies without the use of tools because the M4 is a modular firearm.