Marines fire their M240 machine gun while covering an advance on an objective at a training event during Integrated Training Exercise 2-15 at the Marine Corps Air Ground Combat Center in Twentynine Palms, Calif., Feb. 1, 2015. Marines fire their M240 machine gun while covering an advance on an objective at a training event during Integrated Training Exercise 2-15 at the Marine Corps Air Ground Combat Center in Twentynine Palms, Calif., Feb. 1, 2015. SHARE: Download: Full Size (1.93 MB) Tags: photo essays Credit: VIRIN: 747948-K-CTO26-223.jpg Photo Gallery