MK19
From FarCry 2 Wiki
The MK19 (Grenade Launcher) is the most devastating of all the mounted weapons. It fires 40mm grenades like those found in the M67 and the Milkor MGL, but can do so indefinitely. When found in the back of an assault truck, the MK19 is beyond compare, and a cause of great concern to the player if an enemy is seen riding in a truck with one mounted on its back, as one grenade will destroy a vehicle outright. If you find a vehicle with a MK19 on the back, you should really try to keep hold of it.
