U.S. Army Reserve Pvt. Changyun Park, 459th Transportation Company, 377th Theater Sustainment Command, watches the lane as assistant gunner during qualification on the M2 machine gun, Oct. 26, 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.