The Bofors 40 mm gun, often referred to simply as the Bofors gun, is an anti-aircraft/multi-purpose autocannon designed in the 1930s by the Swedish arms manufacturer AB Bofors. It was one of the most popular medium-weight anti-aircraft systems during World War II, used by most of the western Allies as well as by the Axis powers. The shells were manufactured according to a British design after it was discovered that the Swedish shells had much too sensitive a contact fuse, "which functioned on impact with rain drops". Although the shells could nominally reach out to 11,000 yards (10,000 meters), almost all the shells manufactured had self-destroying tracers that detonated the rounds at a range of 4000-5000 yards (3700-4600 meters.) This helped prevent friendly fire incidents or other collateral damage. In addition to the TNT bursting charge, the shell contained a pellet of powdered magnesium and aluminum as an incendiary. Production of ammunition peaked at 12 million rounds per month in the winter of 1944. Ammunition type Contact fused HE/incendiary fixed shell. AP shells were also available. Projectile weight 1.985 lb 0.80 kg Velocity 2890 feet/s 881 m/s Maximum elevation 90 degrees Range 11,000 yards 10,000 meters Altitude 22,800 feet 6950 meters Rate of fire 120 rounds per minuteCollected by Norman Hall D.J Hall 17455 RAN2 shells (complete) for a Bofors 40mm Anti Aircraft Gun used by the R.A.N.See Imagesbofors 40 mm, anti aircraft gun, shell, r.a.n. bofors gun, world war ii, wwii, norman hall