Four sets of eight M107 155 mm High Explosive Projectiles detonate in sequence during a cache reduction portion of a pilot test at Range 114, Marine Corps Air Ground Combat Center Twentynine Palms, California, March 3, 2015, in preparation for the Marine Corps Operational Test and Evaluation Activity assessment. From October 2014 to July 2015, the GCEITF will conduct individual and collective level skills training in designated ground combat arms occupational specialties in order to facilitate the standards-based assessment of the physical performance of Marines in a simulated operating environment performing specific ground combat arms tasks. (U.S. Marine Corps photo by Sgt. Alicia R. Leaders/Released)