The M240B is a general-purpose machine gun. It can be mounted on a bipod, tripod, aircraft, boat or vehicle. The M240B is a belt-fed, air-cooled, gas-operated, fully automatic machine gun that fires from the open bolt position.

Ammunition is fed into the weapon from a 100-round bandoleer containing a disintegrating metallic split-link belt. The gas from firing one round provides the energy for firing the next round. Thus, the gun functions automatically as long as it is supplied with ammunition and the trigger is held to the rear. As the gun is fired, the belt links separate and are ejected to the side. Empty cases are ejected from the bottom of the gun. 

Caliber:                       7.62 mm

Weight:                        27.6 lbs

Rate of fire:                 200-600 rounds per minute

Manufacturer:            FN Manufacturing (Columbia, SC)

Source: http://www.army.mil/fact_files_site/m-240b/index.html