The President of the United States of America, authorized by Act of Congress, July 2, 1926, takes pleasure in presenting the Soldier’s Medal to Sergeant First Class William S. Duncan, United States Army, for heroism at the risk of life not involving conflict with an armed enemy as a member of Battery D, 3d Training Battalion AW (SP), United States Army Training Center, Antiaircraft Artillery, during range firing on 11 December 1957 on the Oro Grande Range, Oro Grande, New Mexico. During the firing, Sergeant Duncan observed a retracting handle of a 50-caliber gun come off in the hand of a trainee attempting to clear the top right machine gun, causing the bolt to move slightly to the rear, and exposing a live round in the chamber. Realizing the serious danger which existed to the gun crew and observing personnel if the heat of the gun caused the shell to explode, Sergeant Duncan, without hesitation or regard for his personal safety, rushed to the gun, pulled the trainee to a safe distance and cleared the mount of other personnel. In attempting to force the bolt back into battery with the end of the retracting handle to completely close the cover and eliminate the possibility of injury should the round explode, the shell exploded in Sergeant Duncan’s face, causing powder burns and a severe laceration to his left eye. His prompt and courageous action prevented possible death or serious injury to the gun crew and observing personnel and reflects the utmost credit upon himself and the military service.