"The Gsap (Gunsight Aiming Point) camera photographs the gunsight as well as the target and the accuracy of aiming. It is automatically synchronized to take a picture of the sight as the gun fires. The camera's importance in aerial photography is three-fold: it simulates actual firing without waste of ammunition: it permits evaluation of mistakes made; when used in combat, it serves as a valuable record of the firing that takes place. 11th CCRC, AAF Station 112, England. 10-Apr-43."