Which is a common type of machine gun used by the USMC?

The M240 is a common type of machine gun used by the United States Marine Corps. It is a belt-fed, gas-operated machine gun that fires the 7.62x51mm NATO cartridge, making it suitable for diverse missions, including infantry support and vehicle operations. The versatility and reliability of the M240 have made it an essential asset in various combat scenarios, where sustained firepower is necessary.

In contrast, other options serve different purposes within the USMC arsenal. The M203 is a grenade launcher that attaches to rifles and is used for indirect fire support, while the M16 is a lightweight, air-cooled, gas-operated rifle typically used for individual marksmanship rather than sustained automatic fire roles. The M9 is a semi-automatic pistol designed for personal protection and close-quarters engagements, rather than fulfilling the role of a machine gun.

Therefore, the M240 stands out as the correct answer as it fulfills the function of providing sustained automatic fire, which is a primary characteristic of machine guns in combat scenarios.