Public domain
Twenty-millimeter machine guns for planes. The muzzle break of a machine gun for the Air Corps must be right. An inspector in a big auto plant now converted to war work examines each piece as it travels down the production line. Oldsmobile, Lansing, Michigan
From the collection of Library of Congress. Free to download, adapt and use — no permission needed.
Credit lineTwenty-millimeter machine guns for planes. The muzzle break of a machine gun for the Air Corps must be right. An inspector in a big auto plant now converted to war work examines each piece as it trave. 1942-01-01. United States. Office For Emergency Management, Palmer, Alfred T.. Farm Security Administration/Office of War Information Collection, Library of Congress. Public domain.