PAINTBALL TRAINING U.S. Air Force airmen use paintball equipment to simulate live fire during military operations and urban terrain training for Operation Northern Thunder on Fort Harrison, Mont., May 16, 2009. The airmen, assigned to the 185th Air Refueling Wing's security forces, are based in Sioux City, Iowa. SHARE: Download: Full Size (0.08 MB) Credit: VIRIN: 953576-S-OKH17-800.jpg Photo Gallery