Self-propelled 40 MM Anti-aircraft Gun System. In 1951 production started on the M-42. Production stopped in Dec. 1953 after the Cadillac motors car division of General Motors made 3,700. Many components are also used in the M41 light tank and the M37 self-propelled 105 mm gun. A 6 man crew was needed to fire and load the two 40mm guns. Although they never really saw much action as anti-aircraft weapons, the M42’s two 40mm guns were highly effective in the ground support role in Vietnam. 480 40mm rounds were carried. The engine is a continental AOS-895-3 6-cylinder, air-cooled supercharged gasoline engine, 500 hp. Two Dusters are on display exhibiting the front and back. These pictures are from a military vehicle museum the American Society of Military History based in South El Monte, CA. These pictures are Copyright 2009.