There was a need to replace the M13 so development started on the M16 Multiple Gun Motor Carriage in December 1942.2
The M16 had two cargo boxes at the rear.
The rear compartment had all its internal fittings removed and the M45 mount was fitted.2 The mount had to be raised 6" / 152 mm to clear the sides.2 There was no rear door and the tops of the sides were hinged so that they could be lowered.2
Traverse 60° per second. 400-500 rounds per minute. There was enough ammunition carried to allow the M16 to fire for eight minutes of sustained fire.2 Range of 7,200 yards.
Interrupter switches prevented guns from firing when entering drivers compartment area. Used Maxson turret.
The gunner would sit on a seat reclined at 45°. The sight was positioned so that the gunner could follow the sight so he wouldn't have to move. The control grips were on a handlebar that were located on a post between his knees. By rotating the handlebar would rotate the gun or raise and lower it.