Marines with 81mm mortar platoon, Weapons Company, Battalion Landing Team 3/1, conduct gun drills here Sept. 11 to prepare for a live-fire exercise. The battalion is the ground combat element for the 11th Marine Expeditionary Unit, which is conducting its second sea-based exercise since becoming a complete Marine air-ground-task force in May. - Marines with 81mm mortar platoon, Weapons Company, Battalion Landing Team 3/1, conduct gun drills here Sept. 11 to prepare for a live-fire exercise. The battalion is the ground combat element for the 11th Marine Expeditionary Unit, which is conducting its second sea-based exercise since becoming a complete Marine air-ground-task force in May.