Colt Model 1917 U.S. Army revolver, or possibly an earlier Colt Model 1909 Army/Navy/Marine Corps revolver, based on its "COLT D.A. 45" and "UNITED STATES PROPERTY" markings. Both models are built on the large "New Service" frame and were adopted by the U.S. military to use a .45 caliber round during the Philippine-American War and World War I