An automatic double-barreled antiaircraft gun WordNet 3.0 & Open English WordNet

Bofors 40 mm gun is a name or designation given to models of 40 mm calibre automatic anti-aircraft guns designed and developed by the Swedish company Bofors: Bofors 40 mm Automatic Gun L/43 - developed in the 1930s with market entry in 1934, widely used in World War II and into the 1990s Bofors 40 mm Automatic Gun L/60 - developed in the 1930s with market entry in 1936, widely used in World War II and into the 1990s, still in minor use Bofors 40 mm Automatic Gun L/70 - developed in the 1940s with market entry in 1948, widely used in the Cold War to today. Wikipedia