AT-4 SIGHT ALIGNMENT TESTER

The AT-4 is a shoulder fired single shot weapon to which an auxiliary sight may be attached. For sight alignment measurement an optical axis parallel to the bore is established by a mirror mounted to the bore axis reference fixture (right). A second mirror defines the optical axis for the sight bracket. Alignment of these two mirrors are compared using an autocollimator. Offsets in azimuth and elevation are determined to an accuracy of 0.1 minutes of arc. 

The AT-4 Sight Alignment Tester shown at left was developed for the U.S. Army Research and Development Command, Dover, NJ.