Kulsprutegevär m/40

Lore & Background

The Kg m/40 was developed from a patent from 1933, registered in most countries to Ivar Joseph Stack and Axel Torsten Lindfors, and in Canada and the United States to Hans Lauf. The patented design, known as LH33, was chambered in 6.5×55mm Swedish and unsuccessfully marketed in the United Kingdom as the Lindfors gun. When Adolf Hitler announced open rearmament in 1935, Hans Lauf patented a similar design known as LH35 and an improved version the following year, the LH36. The Knorr-Bremse MG35/36 was developed from these patents and chambered in 7.92×57mm Mauser; it was initially rejected by the Wehrmacht but later manufactured by Waffenfabrik Steyr after improvements by Wendelin Przykalla in 1939, with 500 ordered.

With the advent of war in Europe, Sweden urgently needed light machine guns. In June 1940, the Swedish Army Materiel Administration awarded a contract to AB Emge (later Svenska Automatvapen AB, or SAV), which counted Lindfors among its founders, to manufacture and deliver 2,500 Kg m/40s between January and May 1941. Additional orders followed: 125 in autumn 1941, and 2,300 between September 1942 and June 1943. Manufacturing was sub-contracted to various factories in the Stockholm area, with SAV only assembling the rifles. Quality was poor; comparative trials in early 1941 were plagued by accidents and malfunctions. In June 1941, the rifle was deemed unfit for mass production, and all previously delivered guns were returned for adjustments. In total, 4,926 rifles were delivered, one more than contracted, with the last in September 1943.

The Kg m/40 possessed a locking mechanism similar to the ZB vz. 26 and used a 20-round magazine interchangeable with the Kg m/21 and Kg m/37, loaded from the left. It was unpopular with the Swedish Army and passed to the Home Guard, who discarded them in favor of the Kg m/21 soon after the war. During World War II, Swedish-trained Danish troops were offered the rifle but were unhappy and received the Kg m/37 instead; the Norwegian government ordered 480 rifles.

Reader's Guide

The Kg m/40 was a product of Sweden's urgent need for light machine guns during World War II, born from a design lineage that included the LH33, LH35, and LH36 patents and the German Knorr-Bremse MG35/36. Its development was marked by hasty production and poor quality, leading to accidents and malfunctions during trials. Despite contracts for over 4,900 rifles, the weapon never met expectations and was never able to replace the more costly Kg m/37. Its service was brief and confined largely to the Home Guard, who quickly replaced it with the older Kg m/21 after the war. The rifle's legacy is one of a stopgap measure that failed to satisfy its users, earning the unflattering nickname 'galloping iron bed' for its punishing recoil. It also saw limited export to Norwegian forces training in Sweden, while Danish troops rejected it outright. The Kg m/40 remains a footnote in Swedish small arms history, illustrating the challenges of wartime procurement and the compromises made when production speed outweighed reliability.

Did You Know?

• The Kg m/40 was nicknamed 'galopperande järnsängen' (the 'galloping iron bed') by soldiers due to its recoil.
• The rifle's design originated from a 1933 patent registered to Ivar Joseph Stack, Axel Torsten Lindfors, and Hans Lauf.
• A total of 4,926 rifles were delivered to Swedish forces, one more than contracted.
• The Kg m/40 used a 20-round magazine loaded from the left, similar to the FG 42.