Rct. Jeffrey J. Kenney poses for a photo at Marine Corps Recruit Depot Parris Island, S.C., in 1975. Kenney, now a colonel, currently serves as officer-in-charge of Expeditionary Operations Training Group, II Marine Expeditionary Force Headquarters Group, and is scheduled to retire Dec. 21, 2016 after more than 41 years of active service. (Courtesy photo) - Rct. Jeffrey J. Kenney poses for a photo at Marine Corps Recruit Depot Parris Island, S.C., in 1975. Kenney, now a colonel, currently serves as officer-in-charge of Expeditionary Operations Training Group, II Marine Expeditionary Force Headquarters Group, and is scheduled to retire Dec. 21, 2016 after more than 41 years of active service. (Courtesy photo)

Lance Cpl. Jorge Brito uses the Augmented Immersive Team Trainer to locate virtual enemy tanks at Camp Lejeune, N.C., Dec. 13, 2016. The AITT is designed to be cost-effective by replacing actual training targets with virtual moving targets. Brito is a fire support Marine with 2nd Battalion, 10th Marine Regiment, 2nd Marine Division. (U.S Marine Corps photo by Lance Cpl. Juan A. Soto-Delgado) - Lance Cpl. Jorge Brito uses the Augmented Immersive Team Trainer to locate virtual enemy tanks at Camp Lejeune, N.C., Dec. 13, 2016. The AITT is designed to be cost-effective by replacing actual training targets with virtual moving targets. Brito is a fire support Marine with 2nd Battalion, 10th Marine Regiment, 2nd Marine Division. (U.S Marine Corps photo by Lance Cpl. Juan A. Soto-Delgado)

A contractor with the Infantry Immersion Trainer explains to members of the Office of Naval Research how the IIT helps Marines practice and train in real-life scenarios at Camp Lejeune, N.C., Dec. 7, 2016. The staff of the ONR took a tour of the base and various training facilities to give them a better idea of how their development, testing and evaluation translate to everyday training for the Marines. (U.S. Marine Corps photo by Lance Cpl. Miranda Faughn) - A contractor with the Infantry Immersion Trainer explains to members of the Office of Naval Research how the IIT helps Marines practice and train in real-life scenarios at Camp Lejeune, N.C., Dec. 7, 2016. The staff of the ONR took a tour of the base and various training facilities to give them a better idea of how their development, testing and evaluation translate to everyday training for the Marines. (U.S. Marine Corps photo by Lance Cpl. Miranda Faughn)