U.S. Marines with Black Sea Rotational Force 18.1 conduct high-angle fire training with a Mark 19 40mm grenade launcher during a deployment for training exercise at Novo Selo Training Area, Bulgaria, July 4, 2018. Marines with Weapons Company, 1st Battalion, 6th Marine Regiment conducted five days of live-fire ranges, enhancing their operational capabilities. (U.S. Marine Corps photo by Cpl. Abrey Liggins/Released) - U.S. Marines with Black Sea Rotational Force 18.1 conduct high-angle fire training with a Mark 19 40mm grenade launcher during a deployment for training exercise at Novo Selo Training Area, Bulgaria, July 4, 2018. Marines with Weapons Company, 1st Battalion, 6th Marine Regiment conducted five days of live-fire ranges, enhancing their operational capabilities. (U.S. Marine Corps photo by Cpl. Abrey Liggins/Released)