U.S. Army Reserve Troop List Unit Soldiers with the 4th Expeditionary Sustainment Command out of San Antonio qualify on an M2A1 machine gun during Operation Cold Steel II at Fort Hunter Liggett, Calif., Oct. 20, 2017. Operation Cold Steel is the U.S. Army Reserve’s crew-served weapons qualification and validation exercise to ensure that America’s Army Reserve units and Soldiers are trained and ready to deploy on short-notice and bring combat-ready and lethal firepower in support of the Army and our joint partners anywhere in the world. (U.S. Army Reserve photo by Maj. Maryjane Falefa Porter, 364th Expeditionary Sustainment Command).