What role does the windage knob play while zeroing the M16/A2?

The windage knob is a critical component used to adjust the horizontal alignment of the rear sight on the M16/A2 rifle. When zeroing the rifle, adjusting the windage knob allows the shooter to align the index mark on the aperture with the rear sight line, ensuring that the point of aim matches the point of impact. This alignment is particularly important for achieving accuracy, especially at different distances. Properly adjusting the windage helps compensate for any deviations caused by external factors such as wind, enabling a more precise shot placement and enhancing overall marksmanship with the weapon.