A Sergeant demonstrates how machine guns work to a bomber crew. Image stamped on reverse: 'Keystone Press.' [stamp], 'Passed for publication 5 Aug 1943.' [stamp] and '277482.' [censor no] Printed caption on reverse: 'AMERICAN AIRMEN LEARN COMBAT TRICKS. A Sergeant explains the many intricate parts and the working of machine guns to future air gunners undergoing a strenuous course of training at a U.S. Bomber training Depot in Britain.' Handwritten caption on reverse: 'Most likely Bovingdon.'