Bofors gun

Light 40-mm anti-aircraft gun designed by the Bofors company of Sweden 1929 and used by almost all combatants in World War II. They were highly effective against low-flying ground attack aircraft.

The original models were entirely hand operated and visually sighted, but in the latter part of the war radar predictors and power control were added, improving the chance of hitting the target. It fired from four-round clips at a rate of 120 rpm (rounds per minute) and had an effective ceiling of 1,520 m/5,000 ft.