An empty shell casing from a 105 mm main gun of the Stryker Mobile Gun System vehicle lays on the ground after being ejected during Operation Iron Panzer Dec. 8, 2011. Iron Panzer is a combined live-fire exercise between the U.S. Army’s 3rd Squadron, 2nd Cavalry Regiment, and the German Bundeswehr’s 4th Company, 104th Panzer Battalion. This is the first combined live-fire exercise that will incorporate both the German Leopard 2 tank and the American Stryker Mobile Gun System.