HERE Crew Served MGN Wide View Refraction Sight is the most useful accessory you can ever have.  It will ensure first rounds ON THE TARGET every time.  Helicopter door guns, Humvee Top turrets, Tank Turrets or wherever you have positioned your M2 .50cal, you need R.E.D.  Add Sniper precision to any crew served Machine Gun. Saves over 40% in ammunition Drastically reduces collateral damage Saves Lives