15 June 2023
Michael Heidler takes a look at the Lahti L-39 anti-tank rifle from Finland.
Finland was hardly affected by the devastation of World War I and its soldiers did not take part in the hostilities unless they had voluntarily joined the army of the Russian Tsar. Thus, there was a lack of experience with the new heavy tanks that appeared towards the end. It was not until the 1930s that the Finnish Army began to think about appropriate weapons to counter the new masters of the battlefield.
When Finland resisted Soviet demands to move the border in Karelia, at the end of 1939, the Red Army crossed the border in the early morning of 30 November 1939 to take the areas by force. Despite numerous successful defensive actions in The Winter War, the Fins were unable to counter the Red Army tanks. On 13 March 1940 the war ended with the Moscow Peace Treaty. Finland had to cede large parts of Karelia, including Vyborg, the country's second largest city at the time, and other areas to the Soviet Union.
The military leadership quickly recognised the lack of anti-tank weapons in this war, but only two of their own Lahti L-39 anti-tank rifles and a few British Boys anti-tank rifles were available. As the L-39 proved to be a good weapon, it was proposed as the future standard weapon of the army after the end of the fighting.
Its creator was the well-known Finnish designer Aimo Johannes Lahti who, at the time, worked for the state-owned rifle factory VKT (Valtion Kivääritehdas) and who, among other things, had already developed weapons such as the M/26 machine gun and the M/31 Suomi submachine gun before the war. When the army leadership approached him with the wish to create an anti-tank rifle, he was able to push through a 2cm calibre weapon. At first, the authorities believed that the muzzle velocity of this calibre was too low to penetrate armour, but Lahti disproved this in extensive tests in the summer of 1938. The series weapons were thus produced in calibre 20x138mmB, the same cartridge that was used in the Swiss Solothurn S 18-1000 anti-tank rifle. The B indicates a belted round which spaces on the belt rather than the shoulder, rim or mouth of the case.
Conflicts of competence in the Ministry of War, and the infantry inspector Major General Erik Heinrichs' indecisiveness, delayed the manufacturing decision until 6 September 1939. The new weapon got the official military designation 20mm Panssarintorjuntakiväääri 39 (20mm anti-tank rifle 39), with Lahti's model designation L-39 also being retained.
To increase firepower, Lahti designed the L-39 as a semi-automatic weapon with magazine feed from the top. The gunner could fire a full 10 rounds in rapid succession at the enemy tank before a magazine change was necessary. Due to the magazine, the rear sight and front sight are not centrally located above the barrel axis, but are offset to the left. The recoil was enormous, and although the self-loading mechanism already reduced it, Lahti also fitted a muzzle brake and a padded leather recoil pad. The barrel received a wooden jacket with numerous cooling holes for air circulation. This allowed the rifle to be gripped with bare hands when changing position, even when the barrel was hot.
The L-39 is a gas operated weapon with the piston located beneath the barrel. The gas system is also equipped with a gas pressure regulator to ensure the function even with increasing contamination. The recoil spring was so stiff that it was impossible to cock the weapon with a traditional cocking handle. Instead, a rotating crank lever on the right side of the gun was used to pull the bolt back. However, the mode of operation is unusual for a semi-automatic weapon, because the weapon is not immediately ready to fire again after one shot is fired. The bolt carrier is always caught in its rear position and is only released by operating a special lever integrated in the pistol grip. After this manual release by the gunner, the recoil spring moves the bolt carrier together with the bolt forward, pushing a new cartridge from the magazine into the chamber and tensioning the firing pin spring. Now the gunner can release the shot by pulling the trigger. The intention of this procedure is to enable cooling of the open gun during breaks in fire. Experienced gunners can achieve fire rates of up to 15 rounds per minute including magazine change. The empty cartridge cases are ejected downwards. The large trigger guard protects the gunner's hand from the spent hot brass.
At 100m, the penetration rate was about 30mm of armour steel and at 300m distance still 25mm. The newer Soviet T-34 or KW-1 tanks were, however, much better armoured. Only by careful defensive positioning and rapidly firing into weak area on these Soviet tanks was it possible to destroy them. The weapon was also used against bunkers, and now and then even a low-flying Ilyushin Il-2 Shturmovik was shot down. Normal infantry projectiles could not do much damage to these heavily armoured battle planes. Distant targets could be engaged or at least disturbed by explosive and incendiary projectiles up to several kilometres. The burning of dry forests in which the enemy had taken up position was also popular in the hot summer.
Probably the biggest shortcoming of the L-39 was without doubt its weight. The Finnish soldiers christened it norsupyssy (elephant gun). In the Finnish wilderness, the monster, which is over 2m long with an empty weight of 42kg, had to be dragged over uneven ground. The filled magazine alone weighed almost 7kg. The weapon was equipped with an unusual dual bipod, with two sets of legs, one with spikes for use on hard ground and the other with skids for use on softer ground or snow. The skids also helped when being pulled like a sledge by humans or reindeer.
Production of the anti-tank rifle was pushed forward with great urgency. This was a good thing, as the so-called Continuation War with the Soviet Union began in June 1941. The first 10 pieces left the factory in Jyväskylä on April 10, 1940. In total, the Finnish Army ordered 1,852 pieces of the L-39 and 224 pieces of the fully automatic anti-aircraft model L-39/44. The latter was created by removing the bolt catch. However, the high fire rate strained the mechanics and led to technical problems.
A large number of Lahtis anti-tank rifles survived the war. The official losses amounted to only 312 pieces, and this although the heavy weapon often had to be abandoned during retreats. In the post-war years, these weapons remained in the army depots for a long time, until they were sold all over the world in the 1960s and the rest were scrapped.
Although rare, they do come up for auction from time to time. Live Auctioneers sold a Lahti L-39 in 2019 for £3,277, Cowans sold one for $6,900 in 2013 while Rock Island Auctions had the version with ski supports in 2014 that sold for $6,900, all in the USA. These were live-firing weapons so would not be allowed in the UK unless deactivated to current specifications first. More accessible here is the 1941-dated users manual for the Lahti L-39, which will cost around £31 on international eBay sites. Also, accessories, such as a magazine for the weapon as D&B Militaria had one. Alternatively a set of 10 1940s rubbers buffers from the weapon is listed on the forum of sturmgewehr.com for $116. The same website also had a magazine for $124 and a carry box for $176.
Photos courtesy of James D. Julia/Morphy Auctions (USA), SA KUVA (Finland)
Can't get to the newsagents for your copy of The Armourer? Order it online (now with free postage!) or take out a subscription and avoid the general public for the next 12 months entirely. And if you're confined to quarters, stock up on some bookazines to keep you entertained.
Buy the latest copy or any back issues, either in print or digital editions by clicking on The Armourer.
They were the mightiest of ships, able to project power around the world courtesy of fearsome armament. Now, a new 132 page bookazine, Battleships of WWII, brings their story to life with 85 battleships from seven nations. Here is your guide to why they were built, how they were armoured and fitted out with equipment and weapons, and what action they saw in WWII, from the Atlantic to the Pacific. With colour photos and blueprints, statistic tables and key production details, it’s the ultimate guide to the greatest ships of World War II. Order your print or digital copy here.
Get your WWI collecting fix here. It's Military Collectables of WWI, a special digital magazine from the archives of The Armourer, for only £4.99. Covering Badges of Kitchener’s New Army; Anzac uniforms; shoulder titles; Wound stripes; East Africa uniforms; ID signs; Sweetheart brooches. Then there are medals; Photography in WWI; The black art of propaganda; Great War comic postcards; American Liberty Bonds; Trench art; Princess Mary Christmas box; Canadian recruiting posters. Don't forget weapons, battles and equipment from the Battle of the Somme; Trench mirrors; Collecting the Kaiser’s Battle; Military bugles; Collecting the Battle of Arras. Click here for your digital copy.
How about Tanks of WWII, a 164-page guide to the tanks, commanders and battles of WWII. With over 170 tank prototypes, variants, models from the Axis and Allied nations, plus blueprints, rare photos and 3D illustrations. This collector's bookazine can be yours for just £9.99. Click here for your copy.
Or how about a copy of the Collecting German Militaria bookazine for £7.99? Click here to buy this.