World War II Anti-Aircraft Gun Documentary “Ack Ack”
This WWII Ministry of Information film shows the Ack Ack gun crew using their mobile gun. The narrator speaks about the diverse backgrounds of the recruits, and discusses how the gun (most likely a 40mm Bofors cannon) can fire a shell up to 30,000 feet. A height finder and a predictor are used to come up with a firing solution to hit incoming aircraft. The commentator also notes that enemy planes often fly a zig-zag or other evasive course to avoid being hit, but this can also have a positive outcome in that it prevents bombers from making accurate attacks.