Thread: The Bofors Anti-Aircraft Gun

The widely acknowledged success of the 40-mm Bofors gun has tended to overshadow the fact that the Swedish company of Bofors also made a larger and quite successful 75-mm (2.95-in) anti-aircraft gun. The Bofors concern has always been insistent that this gun was evolved by the company alone, but it cannot be overlooked that the design was being formulated at a time when Bofors was working in close association with the Krupp team resident in Sweden as a means to avoid the terms of the Versailles Treaty. It now seems almost certain that some form of cross-fertilization occurred between the two teams, for almost at the same instant the Krupp team produced a 75-mm (2.95-in) gun that led eventually to the famous German ‘88’ and Bofors produced its 75-mm (2.95-in) Model 1929. The Model 29 differed in many details from the Krupp 75-mm (2.95-in) design, but the two weapons had a very similar performance. Other similarities were that both used a cruciform carriage with a central traverse, and that both guns used barrels of similar length and construction. But whereas the Krupp gun was used in only limited numbers by the German navy and a few South American states, the Bofors model was adopted by the Swedish armed forces in two versions. There were two main models of the Bofors gun, the Model 29 and Model 30. These differed only in detail, but to confuse matters both were produced for export in calibres of 75 mm and 80 mm (2.95 in and 3.15 in). Export versions were sold to Argentina, China, Finland, Greece, Hungary, Iran and Thailand, some in 75-mm (2.95-in) and some in 80-mm (3.15-in) calibre. One of the largest customers was Hungary, which received 80 mm guns; these were used extensively during the period when the Hungarian army was allied with the Germans along the Eastern Front from 1941 to 1944, and more were retained for home defence. In Hungary the Model 29 was known as the 8-cm 29 M. Another 80-mm (3.15-in) customer was the Dutch East Indies, but few of these weapons survived after 1942. The Bofors gun was a sound but unspectacular performer. It used a cruciform firing platform that was lowered to the ground from two wheeled axles, which were then completely removed before firing. A horizontal breech block mechanism was fitted, and this was virtually the same as that used on the Krupp gun. However, the Bofors gun did have one thing that the Krupp design lacked, namely an overall simplicity of design: the Bofors gun had little of the complicated fire-control equipment that was used on the Krupp design and proved to be easy to operate, even in the hands of relatively untrained personnel. Thus when the Bofors gun was used in China it proved to be remarkably effective, and the type was chosen for its overall simple approach by such armed forces as those in the Dutch East Indies, which had to rely on a personnel force with few technical assets. Overall, the Bofors gun was a sound gun but one that was soon outperformed by later designs.

The Swedish Bofors Model 29 was sold to various countries in both 75-mm (2.95-in) and 80-mm (3.15-in) calibres. It was a sound design produced by Bofors when German designers were working in Sweden on the 88, and so there were many design features common to the two.

• Specification:
• Bofors 8-cm 29M
• Calibre: 80 mm (3.15 in)
• Weight: travelling 4200 kg (9,259 lb) and firing 3300 kg (7,275 lb)
• Dimensions: barrel length 4.0 m (13 ft 1,6 in)
• Elevation: +807-3°
• Traverse: 360°
• Maximum effective ceiling: 10000 m (32,810ft)
• Shell weight: 8 kg ( 17.6 lb)
• Muzzle velocity: 750 m (2,461 ft) per second

Original Thread

British gunners developed a new anti-aircraft tactic at Valletta. Instead of firing at individual planes, a box of bursting fire and metal was made which increased the average number of hits.