In 1922, the Swedish Navy ordered 2-lb. “Pom Pom” guns as anti-aircraft guns. By 1928, the 2-pounders were inadequate and he Swedes began seeking out a replacement. They approched Bofors, a Swedish steel producer, about a replacement cannon. Bofors got to work on their 40 mm design and fired it off in 1930.
The development wasn’t without problem. The shells are huge, and to get the rate of fire the Swedish Navy demanded, they had to lighten them up. They tried a zinc casing that burned up when fired, but this just crudded up the inside of the barrel. Finally they tried a rear ejection system and a gravity-assisted “throwing” mechanism that would get the next shell into the breach. Eureka!
Now you had a gun capable of firing a 40 mm shell at about 120 rounds per minute. Mounted to a carriage that can turn 180 degrees and raise the barrel between -5-degrees and +90-degrees, the Swedes had a formidiable weapon to put aboard ships and submarines.
By the end of the 1930s, the world was outfitted with Bofors. As the nations scrambled to choose sides, the Bofors would be used on both sides as an anti-aircraft, anti-ship and anti-tank weapon. In fact, the Bofors is still in use today. You can find them on the mighty AC-130 gunships pointing down at the ground. The L70 variant, that Bofors designed at the end of WWII with a higher rate of fire and faster muzzle velocity to be able to stop the faster jet aircraft, is still used today on the Swedish CV90 Army Combat Vehicle, and by the Republic of Korea.
At the same time Bofors introduced the uprated L70 40mm gun, they introduced a 57mm gun. This gun, arguably part of the family tree stemming from that first gun in 1930, is still used by the Swedes, Americans, Brits, Canucks, Finns, and many others as a naval anti-aircraft gun.
Impressive longevity.
[Image Credit: Public Domain]
One of my favorite uses for the Bofors is in the AC-130 Spectre gunship. Its just one of the many guns it has but its also kind of interesting to see it used as a piece of artillery.
<img src="http://upload.wikimedia.org/wikipedia/commons/thumb/3/31/AC-130A_pylon_turn.jpg/800px-AC-130A_pylon_turn.jpg" width=600 />
The incredible thing is the Bofors was supposed to be either ground or ship mounted. The Air Force and Lockheed decided it would be a good idea to put one on a cargo plane. The result is some awesomeness.
And the Bofors is only the second biggest gun on the AC-130! Don't forget the 105mm howitzer. http://en.wikipedia.org/wiki/M102_howitzer
Oh trust me I haven't forgetting them or the miniguns. The Spectre takes the idea of Puff the Magic Dragon (AC-47) and runs with it. Puff looked so simple compared to what we turned them into. Now we just need to stuff a daisy cutter into the cargo hold of an AC-130 and really go play.
Sure helps to have air superiority doesnt it?
In Dubya-Dubya-Dos it was fired by a dude sitting in a seat with a pedal on the floor, just like a really explody car accelerator.