Lahti L-39

Lahti L-39
A Lahti L-39 anti-tank rifle.
Type	Semi-automatic anti-tank rifle
Place of origin	Finland
Service history
Used by	Finland
Wars	Winter War, World War II
Production history
Designed	1939
Manufacturer	Valtion Kivääritehdas (VKT)
No. built	~1,906
Variants	L-39/44 anti-aircraft
Specifications
Weight	49.5 kg (109 lb)
Length	2,200 mm (87 in)
Barrel length	51.2 in (1,300 mm)
Cartridge	20×138mmB
Caliber	20 mm (0.79 in)
Action	Gas-operated
Rate of fire	Max. 30/min
Muzzle velocity	800 m/s (2,600 ft/s)
Feed system	10 rounds box magazine

The Lahti L-39 is a Finnish 20 mm anti-tank rifle used during the Second World War. It had excellent accuracy, penetration and range, but its size made transportation difficult. It was nicknamed "Norsupyssy" ("Elephant Gun"), and as tanks developed armour too thick for the Lahti to penetrate its uses switched to long range sniping, tank harassment and with the L-39/44 fully automatic variant, employment as an improvised anti-aircraft weapon.

Aimo Lahti had doubts about the original idea of a 13 mm anti-tank machine gun and started working on a 20 mm design. Officers who wanted smaller calibre anti-tank weapons believed that the muzzle velocity of 20 mm shells was insufficient to penetrate armour and a weapon with a higher rate of fire and in a smaller calibre would prove useful. As a result, Lahti designed two competing anti-tank weapons: a 13.2 mm machine gun and a 20 mm rifle. After test firing both weapons in 1939, they found that the 20 mm rifle displayed better penetration.

The rifle is a semi-automatic, gas operated weapon with the piston located beneath the barrel and ammunition feed from detachable top-mounted magazine with bottom ejection for the spent cartridges. To reduce recoil, the rifle is equipped with a five hole muzzle brake and a padded leather recoil pad. The barrel had a wooden jacket as to allow transportation after firing.

During the Winter War (1939–1940) Finland lacked anti-tank weaponry. Only two 20 mm rifles and a few 13.2 mm machine guns made it to the front, where the 13.2 mm machine guns were found to be ineffective and unreliable while the larger 20 mm rifles proved successful against Soviet armour. Because of this, Finland finally settled on the 20 mm design and started production.

The gun was also widely used in the Cold Charlie counter-sniper technique, where the Finns would use a mannequin posing as an officer sloppily covering himself. Soviet snipers would fire upon the mannequin, and the Finns would then return fire at the Soviet snipers with the Lahti L-39.