A round leaves the chamber of a Marine’s M4 carbine assault rifle during Expeditionary Operations Training Group’s close quarters tactics course before he switches to use his pistol at Camp Lejeune, N.C., Nov. 3, 2015. These drills tested the Marines with 2nd Reconnaissance Battalion’s ability to change between the two weapons systems, simulating a malfunction or depleting their ammunition. (U.S. Marine Corps photo by Lance Cpl. Dalton A. Precht/Released) - A round leaves the chamber of a Marine’s M4 carbine assault rifle during Expeditionary Operations Training Group’s close quarters tactics course before he switches to use his pistol at Camp Lejeune, N.C., Nov. 3, 2015. These drills tested the Marines with 2nd Reconnaissance Battalion’s ability to change between the two weapons systems, simulating a malfunction or depleting their ammunition. (U.S. Marine Corps photo by Lance Cpl. Dalton A. Precht/Released)