Q: I just bought a used AR in 6.8mm SPC for deer hunting. It shoots great with the iron sights that came on it, but my groups are always high and to the right. I don't want to put a scope on the rifle because I don't want to add weight. How do I adjust the sights?
A: Adjustable sights frequently utilize screw mechanisms mounted horizontally and vertically in the sight body to cause the sight blade or aperture to move laterally and/or vertically. Some screw-adjustment mechanisms have audible clicks while others do not. Nearly all have graduations inscribed or painted on the sight body and an indicator on the adjustment screw or knob.
Regardless of the mechanism for adjustment, the process is the same: The rear sight is moved in the same direction as the desired change in bullet impact. Thus, to move bullet impact to the left, the rear sight must be moved to the left. With an adjustable front sight, the sight is moved in the direction opposite to the desired change in impact. Since you want to move bullet impact down, you would move the front-sight post up.