U.S. Air Force Staff Sgt. Richard Mulford, 380th Expeditionary Security Forces Squadron Combat Arms Training and Maintenance NCO in charge, right, briefs Senior Airman Andre McCoo, 380th ESFS member, and another Airman on rules of the mobile firing range before they zero their weapons Aug. 24, 2012. Proper aim is achieved when a weapon is "zeroed," meaning its sights are set specifically to the shooter so the shooter can actively and precisely engage a target. (U.S. Air Force photo/Senior Airman Jared Elliott)