A U.S. Marine fires an M2 .50-caliber heavy machine gun during Enhanced Mojave Viper, a training exercise on Marine Corps Air Ground Combat Center Twentynine Palms, Calif., July 10, 2010. A U.S. Marine fires an M2 .50-caliber heavy machine gun during Enhanced Mojave Viper, a training exercise on Marine Corps Air Ground Combat Center Twentynine Palms, Calif., July 10, 2010. SHARE: Download: Full Size (3.39 MB) Tags: photo essays Credit: VIRIN: 582424-D-WXD51-809.jpg Photo Gallery