A U.S. Marine gives a brief prior to beginning the Amphibious Combat Endurance Test on Marine Corps Base Camp Pendleton, Calif. Jan. 15. - A U.S. Marine gives a brief prior to beginning the Amphibious Combat Endurance Test on Marine Corps Base Camp Pendleton, Calif. Jan. 15.

Firefighters with the Marine Corps Air Station Miramar Fire Department decontaminate a Marine with Explosive Ordnance Disposal after he entered the contaminated area during a Chemical, Biological, Radiological, Nuclear and High-Yield Explosives exercise at the gas chamber aboard Marine Corps Air Station Miramar, Calif., May 19, 2016. The exercise revolved around PMO, the Miramar Fire Department, Explosive Ordnance Disposal, and Aircraft Rescue and Firefighting working together to identify and eliminate the threat of a simulated clandestine drug lab. - Firefighters with the Marine Corps Air Station Miramar Fire Department decontaminate a Marine with Explosive Ordnance Disposal after he entered the contaminated area during a Chemical, Biological, Radiological, Nuclear and High-Yield Explosives exercise at the gas chamber aboard Marine Corps Air Station Miramar, Calif., May 19, 2016. The exercise revolved around PMO, the Miramar Fire Department, Explosive Ordnance Disposal, and Aircraft Rescue and Firefighting working together to identify and eliminate the threat of a simulated clandestine drug lab.

Corporal James Lafrance, a Reconnaissance Marine with Force Company, 1st Reconnaissance Battalion, 1st Marine Division, shoots targets with a shotgun during a physical training exercise aboard Marine Corps Base Camp Pendleton, Calif., Nov. 7, 2014. The eight-mile hike had multiple events along the route to test the Marines’ proficiency with various weapon systems. - Corporal James Lafrance, a Reconnaissance Marine with Force Company, 1st Reconnaissance Battalion, 1st Marine Division, shoots targets with a shotgun during a physical training exercise aboard Marine Corps Base Camp Pendleton, Calif., Nov. 7, 2014. The eight-mile hike had multiple events along the route to test the Marines’ proficiency with various weapon systems.

A rifleman with Company L, 3rd Battalion, 1st Marine Regiment, hikes to his company objective during the Marine Corps Combat Readiness Evaluation aboard Marine Corps Base Camp Pendleton, California, Sept. 23, 2014. The MCCRE is designed to be a final evaluation to ensure the Marines are prepared to be deployed. The battalion is slated to deploy as the ground combat element of the 15th Marine Expeditionary Unit next year. - A rifleman with Company L, 3rd Battalion, 1st Marine Regiment, hikes to his company objective during the Marine Corps Combat Readiness Evaluation aboard Marine Corps Base Camp Pendleton, California, Sept. 23, 2014. The MCCRE is designed to be a final evaluation to ensure the Marines are prepared to be deployed. The battalion is slated to deploy as the ground combat element of the 15th Marine Expeditionary Unit next year.