Armor-piercing rounds enter the firing chamber of a .50-caliber M2 machine gun, which belongs to Headquarters and Service Company, 2nd Maintenance Battalion, 2nd Marine Logistics Group during a field exercise aboard Camp Lejeune, N.C., May 9, 2013. Approximately 20 servicemembers with the company used the M2s as part of a four-day training operation in order to maintain combat readiness within the unit.