The GG&G A2 Style BUIS (Back Up Iron Sight) provides the operator with an easy-to-install and easy-to-operate flip up rear sight, and now includes an important locking detent. Once placed in the up position, the sight cannot be folded down without depressing the spring assisted detent release button located on the left side of the sight base. This totally eliminates the possibility of accidentally lowering the sight.
The A2 BUIS can be used as a stand-alone sight or in conjunction with one of our FIRE System interface rails. The A2 BUIS can be used as a co-witness iron sight with most of the red dot sighting systems. Weighing in at just over two ounces, this sight features the standard A2-style double peep aperture and has full windage adjustment. It uses the Colt-style windage knob and windage screw. One click of the windage knob provides approximately 0.48 MOA change when mounted on the M16A2E4 rifle and about 0.65 MOA on the M4 carbine. Initial zero is set by adjusting the weapons front sight post. When in the down position, it will clear most optics. The mount body and sight stem are manufactured from billet 6061 T6 aluminum and hard coat anodized in a non-reflective black mil spec finish to provide combat durability. All steel components are black manganese phosphated per mil spec. Used by armed forces and law enforcement teams word wide.
As an option you can request the XS same plane aperture, or Trijicon Tritium aperture be installed. Except for these optional apertures, all sight components are standard M16A2 sight components.