Airman 1st Class Christopher Jackson, 790th Missile Security Forces Squadron response force leader, examines his target during training Aug. 29, 2018, at Fort Harrison, Mont. Airmen will be testing their skills in realistic weapon scenarios, simulated dismounted operations and combat endurance events as part of the 2018 Air force Defender Challenge. (U.S. Air Force photo by Airman 1st Class Tristan Truesdell)