Reserve Marines with Company A, 1st Battalion, 23rd Marine Regiment, 4th Marine Division, fire their M240 and M2 .50 caliber machine guns during an air assault course at Integrated Training Exercise 4-18, aboard Marine Corps Air Ground Combat Center Twentynine Palms, Calif., June 16, 2018. ITX 4-18 provides Marine Air-Ground Task Force elements an opportunity to undergo service-level competency assessments so that they can seamlessly integrate with active duty Marines in the event of a crises that requires a rapid response. (U.S. Marine Corps photo by Cpl. Dallas Johnson/Released)