Mounted Machine-gun

The Mounted Machine-gun takes two forms. There is the door-mounted machine gun in VTOLS, and there is the Minigun that is een in the Grey Territory cutscene

Trivia
Strangely, even though all VTOLs are armed with the machine gun, in the opening cutscene of Resistance: Fall of Man a VTOL with a mounted minigun can be seen.

In the VTOL carrying you to SRPA base Igloo in the first mission of Resistance 2, Major Blake calls it (the machine gun variant) a cannon when he orders Victor 2 to man it.