The Lahti L-39, commonly nicknamed the Norsupyssy (Finnish for Elephant Gun), is a Finnish anti-tank rifle designed in 1939.
Aimo Lahti had doubts about an older design: a 13.2mm machine gun, which led him to design a 20mm rifle. As officers said that the muzzle velocity of 20mm shells might prove insufficient to penetrate tanks and that a weapon with a higher cyclic rate would prove more useful, Lahti designed two weapons; a 13.2mm machine gun and a 20mm anti-tank rifle. In the end, the rifle won out due to its penetrating power. Only about 1906 were made.
The weapon is gas-operated and is fed by a magazine which holds 10 20mm bullets. Spent shells are ejected from the bottom of the rifle; some weapons have an additional rubber buffer to deflect spent casings. To reduce recoil, the rifle had a shock-absorbing recoil pad made of leather and a five-holed muzzle brake. A wooden jacket surrounds the barrel for easy transportation.
Loading the weapon is simple; simply load 10 rounds into the magazine, insert it and turn the crank on the right side of the weapon about two or three and a half times. Depress the grip safety to close the bolt and pull the trigger to fire. Do not put your fingers in front of the trigger guard; spent casings of the weapon are ejected downwards, and putting fingers in front of the trigger guard can cause those fingers to get crushed by the spent casing. Instead, put your fingers somewhere around the rear of the weapon, preferably near the cheekrest. Even if the weapon has a rubber buffer, putting your fingers in front of the trigger guard is still not recommended.
Due to its weight, the rifle was not really portable; even its magazine was heavy, weighing in at two kilograms. So, in battle, the rifle was assigned a two-man team to move the weapon.
The L-39 has a variant known as the L-39/44, which is a fully-automatic version of the rifle.