M51 gunner of the 455th AAA AW Bn, better known as &quot;The Rabbs.&quot;  Alongside the feminine figure, the crew is  keeping track of their shooting tally on the shield of their M45 turret.   

The mounting bracket for the gun's Mark IX sight is clearly seen on the crossbar, between the soldier's hands.

M51 gunner

Returning the favor - a wounded American medic is helped to an aid station during the Battle of the Bulge in December 1944.

Wounded medic

 The M45 was driven by a 12-volt electric motor connected to two variable speed belt-drives, one for traversing and the other for elevating the turret.  Power was supplied by two 6-volt batteries connected in series.  The batteries were charged by a 300-watt generator connected to a single cylinder, 4-cycle Briggs and Stratton gasoline engine, equipped with a self-starter.  The generator never powered the turret directly.
    A nonlinear speed control system was incorporated with the belt drives in order to provide precise control of the turret at slower speeds.  This aided the gunner in tracking his target. 

     The M45 traversed a complete 360° circle, elevated to a fully vertical 90°, and depressed 10° below horizontal.  Solenoids fired all four M2 HB machine guns simultaneously
 If the batteries went dead, the M45 turret could still be elevated and traversed by hand 

by attaching these manual control rods to the trunnions, as demonstrated by this M51 crew.
 

