The Bofors 40 mm gun, often referred to simply as the Bofors gun, is an anti-aircraft autocannon designed in the 1930s by the Swedish arms manufacturer AB Bofors. It was one of the most popular medium-weight anti-aircraft systems during World War II, used by most of the western Allies as well as some captured systems being used by the Axis powers. A small number of these weapons remain in service to this day, and saw action as late as the Persian Gulf War.Brass shell casing 1955 40 mm. and gold coloured plaque with black writing.40mm. MK4. LOT 428 MF A^N 1955. Plaque: Bofers 40mm Mk II Anti-Aircraft Gun Dated 1955.anti-aircraft gun, shell casing, brass, wwii, world war 2, bofers