UNDER COVER U.S. Air Force Airman 1st Class Chadwick Richardson uses an M-240 machine gun to provide cover in a defense fighting position during training held on Ellsworth Air force Base, S.D. Oct. 22, 2008. Richardson is assigned to the 28th Security Forces Squadron. SHARE: Download: Full Size (0.07 MB) Credit: VIRIN: 291378-B-BBW91-316.jpg Photo Gallery