In the later stages of World War I, the Swedish Bofors company, which was aware of the needs of air defense operations, developed its own anti-aircraft gun, but performed poorly in the test, and the company's senior management did not give up in order to grab the anti-aircraft gun market cake, but increased investment, and in 1928, it obtained a naval contract to develop a 40 mm caliber anti-aircraft gun, which is the origin of the Bofors 40mm L/60 anti-aircraft gun.
Rooted in terms of roots, the Bofors 40 mm anti-aircraft gun has a British gun pedigree, and the Swedish Navy purchased the British Vickers 2-pounder "Bang Bang Gun" (40 mm caliber) in 1922, which will obviously be used as a technical reference. Bofors's strength is metallurgical and metalworking capabilities, they are confident of producing the right barrel, allowing the ammunition to obtain better ballistic characteristics, the problem is how to achieve a higher rate of fire for single-barrel structures.
Through repeated experiments, the rate of fire was increased to 130 rounds per minute after improving the feed and shell discharge systems, which was already very good for a 40 mm caliber gun, the prototype gun was tested in November 1931, and by 1933 it was ready for production, it was called "40 mm akan M/32" or "Bofors 40 mm L/60".
The first good fortune of the Bofors 40 mm anti-aircraft gun came from the Belgian shooting experiment in 1935, when it was compared with the British anti-aircraft gun, and it turned out that Bofors products were not only better in terms of ballistic characteristics, but also the barrel adjustment speed was far superior to other guns of the same type, the hit rate was 3 times that of the British anti-aircraft guns, and the field maneuvers and battles were also carried out quickly. What is more valuable is that there are representatives of the French Army at the test site, France as a traditional European army power has always looked down on the artillery of other countries, this time for the first time to give praise and buy, is simply the best advertising.
Bofors 40 mm anti-aircraft guns had become a well-known product before World War II, with a total of about 1,500 units sold by 1939, mainly from Britain, Belgium, the Netherlands and Argentina. Even the best weapons had to prove themselves in real combat, and the outbreak of World War II soon after gave the Bofors 40 mm anti-aircraft gun a chance.
During World War II, the Bofors 40 mm anti-aircraft gun was widely used in the army and navy, and there were several versions produced in different countries, for example, the United Kingdom made appropriate modifications to the gun to facilitate mass production, and introduced a complex mechanical fire control device - Kerrison Director, which was named QF 40 mm Mark I in the United Kingdom.
The United States was another major producer during World War II, when it secretly purchased an anti-aircraft gun and corresponding test munitions in July 1940, and later the Chrysler Company of Detroit was responsible for the main production work, producing about 60,000 anti-aircraft guns and about 120,000 barrels during World War II.
After World War II, the Air Force ushered in the jet age and the missile age, which was a major challenge for the survival of all types of anti-aircraft guns, new aviation targets flew higher and faster, leaving a short window for the attack of anti-aircraft guns, and Bofors soon improved and upgraded the anti-aircraft guns.
On the one hand, the use of a longer diameter barrel, firing a larger 40×365R ammunition, the initial speed of the muzzle increased from the original 881 m / s to 1021 m / s, the maximum range from 7160 m to 12500 m, the rate of fire was also increased to 240 rounds / min; on the other hand, the anti-aircraft gun frame introduced electrical auxiliary equipment to improve flexibility. The new generation of the Bofors 40 mm anti-aircraft gun became NATO standard equipment in 1953.
Advances in electronic technology have played a beneficial role in the continuation of the Bofors 40 mm anti-aircraft gun, after all, the anti-aircraft gun needs to be accurate, for example, the Dutch "flytrap" radar fire control system is a system with all-weather combat capabilities, which can guide 3 anti-aircraft guns to combat at the same time.
The development of self-propelled anti-aircraft guns and infantry fighting vehicles has also brought benefits, far from saying that the PASARS-16 short-range anti-aircraft vehicle developed by Serbia in recent years uses the Bofors 40 mm L/70 anti-aircraft gun, and Sweden's own CV90 infantry fighting vehicle also uses it (it also has versions of the 30 and 35 mm cannons).
In the current technology of electromagnetic gun is a very advantageous development direction, the development of traditional artillery room has been very small, in the 40 mm caliber of this level has not seen which gun has a clear advantage over the Bofors 40 mm gun, it seems that it will continue to serve for a long time.