The sights of the rifle are adjustable for both windage and elevation. Windage adjustments are made on the rear sight; elevation adjustments are made on the front sight.

Figure 3-25.-Front sight, M16A1.

The rear sight consists of two apertures, as shown in figure 3-23, and a windage drum with a spring-loaded detent, as shown in figure 3-24. The aperture marked "L" is for use for ranges beyond 300 yards; and the unmarked aperture is for use for ranges from 0 to 300 yards. Adjustments for windage are made by pressing in on the spring-loaded stud with either a pointed instrument or the tip of a cartridge and rotating the windage drum in the desired direction.

The front sight of the Ml6A1 rifle consists of a rotating sight post with a spring-loaded stud (fig. 3-25). Adjustments are made by using a pointed instrument or a tip of a cartridge. To raise or lower the front sight post, depress the spring-loaded stud and rotate the post in the desired direction of change. A spring-loaded detent keeps the post from being moved accidentally. To raise the strike of the bullet, depress the detent and rotate the sight post clockwise.

Each click of elevation or windage adjustment will move the strike of the bullet a specific distance at a specific range. At a range of 100 yards, one click of either elevation or windage on the sights of the rifle will move the strike of the bullet approximately 1 inch, or 2.54 centimeters, up or down.