U.S. Marine Corps Lance Cpl. Jon D. Romero fires a .50 caliber GAU-21 machine gun from a UH-1Y Venom helicopter during exercise Koolendong 13 in Australia, Sept. 2, 2013. Romero, a crew chief, is assigned to Marine Medium Tiltrotor Squadron 265 Reinforced, 31st Marine Expeditionary Unit. Three Venom helicopters and four MV-22 Osprey aircraft are being used in the exercise. U.S. Marine Corps Lance Cpl. Jon D. Romero fires a .50 caliber GAU-21 machine gun from a UH-1Y Venom helicopter during exercise Koolendong 13 in Australia, Sept. 2, 2013. Romero, a crew chief, is assigned to Marine Medium Tiltrotor Squadron 265 Reinforced, 31st Marine Expeditionary Unit. Three Venom helicopters and four MV-22 Osprey aircraft are being used in the exercise. SHARE: Download: Full Size (3.18 MB) Tags: Photo Essays Credit: VIRIN: 231482-K-YGK36-919.jpg Photo Gallery