Marines prepare to fire an AT4 antitank grenade launcher as they receive instructions from Marines assigned to a tactical training control group as part of Integrated Training Exercise 2-15 at the Marine Corps Air Ground Combat Center in Twentynine Palms, Calif., Feb. 15, 2015. Marines prepare to fire an AT4 antitank grenade launcher as they receive instructions from Marines assigned to a tactical training control group as part of Integrated Training Exercise 2-15 at the Marine Corps Air Ground Combat Center in Twentynine Palms, Calif., Feb. 15, 2015. SHARE: Download: Full Size (2.06 MB) Tags: Photo Essays Credit: VIRIN: 401897-I-MUL77-706.jpg Photo Gallery