|Weight||10 kg||8.5 kg|
|Length||1280 mm||1257 mm|
|Barrel length||500 mm||685 mm|
|Feed||box magazine, 25 rounds||box magazine, 20 rounds|
|Rate of fire||500 rounds per minute||480 rounds per minute|
In 1940 Sweden, feeling the lack of light machine guns then in service, bought a manufacturing licence for a relatively unknown (and hardly successful) light machine gun which was developed during the mid-thirties by Hans Lauf at the German car brake manufacturing company, Knorr-Bremse. The same weapon, chambered for 7.92 Mauser ammunition, was produced for Knorr-Bremse by Steyr factory in Austria. It was purchased in limited numbers as MG-35/36 by the German Waffen SS but proved unreliable, and in Germany it was used mostly for training. The “Swedish Knorr-Bremse” was produced by the Svenska Automatvapen AB (SAV) company under licence. This weapon was offered to the Swedish government and it was quickly adopted as the Kg m/40. Unlike most other Swedish- or German-made machine guns, the m/40 was very unpopular among soldiers, because of its poor reliability. About 5,000 m/40 machine guns were delivered to the Swedish government between 1940 and 1943, and most were quickly passed down from the Army to the Home Guard; soon after the war the Kg m/40 were withdrawn from Home Guard service.
The Kg m/1940 light machine gun was developed from the German Knorr-Bremse MG.35/36 light machine gun, but with certain changes, such as a different caliber, omission of the selective-fire capability, and a different magazine.
The Knorr-Bremse light machine gun is a gas operated, air-cooled, automatic-only (Kg m/40) or selective-fire (MG 35/36) weapon that fires from an open bolt. The long-stroke gas piston is located above the barrel, in the long gas tube, which runs all the way to the muzzle. The gas tube is connected to the bore of the barrel via two curved gas channels. Barrel locking is achieved by a vertically tilting bolt, which is linked to the gas piston rod by a swinging link.
The Knorr-Bremse light machine gun uses only a magazine feed system. The feed is from the left side, with ejection to the right. Swedish Knorr-Bremse m/40 machine guns used modified Swedish BAR (m/21 or m/37) magazines, while German Knorr-Bremse MG-35/36 used 25-round "Dreyse" MG-13 magazines.
The Kg m/40 is fitted with a carrying handle and folding bipod, both attached to the gas piston tube. Rear sights are of the aperture (diopter) type on Swedish guns and of open, V-notch type on German guns.