Illustration of the M39 pedestal mount for the .50 caliber machine gun. (Source: TM 9-230: Machine Gun Mounts for Boats, War Department Technical Manual, October 1943.)

Figure 1—Cal. .50, Machine Gun, Pedestal Mount M39, with Aircraft Machine Gun
Illustration of the M39 pedestal mount for the .50 caliber machine gun. (Source: TM 9-230: Machine Gun Mounts for Boats, War Department Technical Manual, October 1943.)
Figure 1—Cal. .50, Machine Gun, Pedestal Mount M39, with Aircraft Machine Gun