Sgt. Jonathan Temple, right, and Sgt. Manuel Soto Jr., left, motor transport operators with Motor Transport Company, Marine Wing Support Squadron (MWSS) 371, supervise a Marine firing an MK-19 grenade launcher at Yuma Proving Grounds, Ariz., June 16. Marines with MWSS-371 conducted crew-served weapons training with MK-19 grenade launchers and M2 .50-caliber machine guns mounted onto 7-ton trucks and Humvees to hone their skills and increase their readiness. (U.S. Marine Corps photo by Sgt. Brytani Wheeler/Released) - Sgt. Jonathan Temple, right, and Sgt. Manuel Soto Jr., left, motor transport operators with Motor Transport Company, Marine Wing Support Squadron (MWSS) 371, supervise a Marine firing an MK-19 grenade launcher at Yuma Proving Grounds, Ariz., June 16. Marines with MWSS-371 conducted crew-served weapons training with MK-19 grenade launchers and M2 .50-caliber machine guns mounted onto 7-ton trucks and Humvees to hone their skills and increase their readiness. (U.S. Marine Corps photo by Sgt. Brytani Wheeler/Released)