How does one define the best anti-aircraft gun of all time? The specs on paper do not tell the whole story. That is because there are always tradeoffs to be made in this, or any field of military weapons. High performance comes with costs – not just financial, but in terms of weight, complexity, maintenance needs, and proper training of the operators – to name just a few of the things that have to be balanced.
When a system gets it right, it becomes a classic. For anti-aircraft guns, the standard is arguably the 40mm Bofors. It packed a punch – about two and a half ounces of high explosives as used by the United States. But this wasn’t an American-designed weapon. Bofors is actually a Swedish company, and Sweden was neutral in World War II. The gun is still produced today, and is still seeing action.
What did that mean? Well, this gun was bought by the United Kingdom before the war, and in 1940, the United States began to build it (the Army having tested a version in 1937, according to NavWeaps.com). And they weren’t the only users. Hungary, a German ally, built some for the Nazis, who also captured a large number of these guns in the early years of World War II. Japan also built some, copied from captured British mounts.
The Bofors 40mm saw action from land and sea mounts. The land versions were usually single mounts, but twin mounts were also used in vehicles like the M42 Duster and the failed M247 Sergeant York. On sea, the primary mount – and most effective version – was the quad 40mm mount, but twin and single mounts were also used.
The Bofors had a maximum range of 11,133 yards and could hit targets just over 22,000 feet high. It could fire as many as two rounds a second, but given the need to manually reload with five-round clips, it was more likely to fire about 90 rounds a minute tops.
The Bofors 40mm was barely enough to handle the kamikazes that the United States was facing in 1945, but the end of World War II meant its replacement by a new three-inch gun was only a partial one. The mounts hung around through parts of the 1980s with the United States Navy.