U.S. Air Force Airman 1st Class Tiana Zakariyyaa, 633rd Security Forces Squadron member, counts the bullets in an M4 carbine magazine while wearing a gas mask at Langley Air Force Base, Va., Nov. 1, 2012. The shooting exercise was held to assess how accurately security personal score on the qualifications, through various challenges. (U.S. Air Force photo by Airman 1st Class Victoria Taylor/Released)