my father, Virgil Simpson, sitting on the armor shield of the Quad 50 (or M51), somewhere in Europe, circa 1944;
Virgil was a cannoneer, then the gunner, on this antiaircraft weapon.

Virgil On The Quad 50; Europe, Circa 1944

a quad 50 (or M51) in Europe, during World War 2;
My father, Virgil Simpson, was a cannoneer, then the gunner, on this anti-aircraft weapon. 
This quad 50 was trailer mounted and hitched to a truck, whenever it was moved to different location.
The four .50 caliber guns, electrically operated, were mounted on a turret and could be moved both up and down and side to side. 

Quad 50 In Europe; Circa 1944

My father, Virgil Simpson, was a cannoneer, then the gunner, on this antiaircraft weapon.
The cannoneers changed out the ammo cans for the 4 guns, whenever they became empty. 
Before Larry Kreeger took over command of this weapon, Don Trites was in charge. Don told me, in a letter, that he liked for my father to be the gunner, because Virgil remained calm and collected under fire.