20mm Anti-Tank Gun vs 16 Steel Sheets

Watch as Full Mag Youtuber fires a Finnish Lahti L-39 anti-tank gun at 16 1/4 inch steel plates spaced out between 4 inches. Using armor piercing Tungsten rounds to see how many steel it can punch through. The weapon utilizes skis and a special bipod to stabilize the recoil.

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 (creator) 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.

Several of the rifles remained in service after World War II serving as an anti-helicopter weapon, while many others were sold to collectors, mostly in the United States. Today the rifles, especially those in working condition, are quite rare and highly sought after. Some deactivated weapons (with a steel bar welded into the chamber) have been reactivated due to their value. Ammunition is rare. Often they are rechambered to .50 BMG to lower the cost of use.

In the United States of America, civilian ownership remains possible, depending on state and federal laws. Because the weapon fires rounds larger than .50 calibre, it is considered a destructive device and is subject to the 1934 National Firearms Act. Civilian ownership is dependent on compliance with this law and whether one’s state law prohibits civilian ownership of destructive devices.

Users found the L-39 to be heavy and difficult to move in the battlefield. Even its magazine weighed almost two kilograms. The magazines had a covered viewing slit on the right side to indicate the number of rounds left in the magazine, and a 15-round magazine was later developed for anti-aircraft use.

The whole weapon weighed some 50 kilograms and it was usually towed by horses, but when stripped down could be carried by several men. The rifle had adjustable iron sights calibrated between 200 and 1,400 meters and was equipped with 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.

In the field, a two-man team was assigned to the gun to move and fire it. Some rifles were abandoned in the heat of battle, but they were easy to replace. By the end of the war over 1900 L39s had been manufactured by VKT (Valtion Kivääritehdas, “State Rifle Factory”, modern day Patria) and put in the field.

Video Transcription

The Breakdown is where I take your favorite parts in movies and videogames, and show ’em to you in real life. This episode: World of Tanks.

World of Tanks is a Free to Play online game where you battle tank vs tank in epic armored warfare. In-game you’ll have access to over 450 tanks from powerful steel brawlers to light-and-fast scouts. The folks over at Wargaming who sponsored this video wanted to see an anti-tank rifle in action.

The Finnish Lahti L-39 Anti-tank rifle was manufactured by VKT and fires a 20mm round. Its unique design incorporates skiis and a stabilizing bipod that folds down to anchor the rifle for recoil.

After the first and second world wars,tanks saw significant upgrades in armor with the types of materials and thickness utilized. So instead of firing at a tank, today I’ve set up sixteen quarter-inch steel plates, and I’m gonna load up one of the original almost eighty-year-old armor-piercing tungsten rounds, to see how many plates we can punch through.

So I tried to figure out the easiest platform I could build these quarter-inch steel plates and hold ’em in place, so it’s rigid enough to see how many sheets it’ll go through, but not so rigid that I run the risk of a ricochet, because that’s the last thing you want to do. Generally whenever you see steel targets like that in the background, whenever you’re shooting at steel, it’s at a little bit of an angle, it’s not completely profile, so you don’t run the risk of a ricochet or fragmentation or anything. So what I did was, I took two-by-fours here and I numbered ’em, so I’m gonna have fifteen rows of quarter-inch steel here, and I just gotta take the time to put ’em in here. The good thing is, it’ll be rigid enough to hold ’em in place, but it’ll be flexible enough so that as soon as it hits, if it needs to move, I guess it can. I would say “what’s the worst that could happen” but we don’t wanna see that. So we got champion at the range today, we got Donnie! Donnie! Donnie’s hanging out at the range today! Say hi!

Donnie: “What’s up guys?”

[laughter] he’s so good.

[montage of building]

It’s coming together a lot faster than what it took to make the platform.

The last screw, so sixteen sheets, not fifteen. It was originally gonna be fifteen, but it just seemed easier to make it an even four inches of steel plates here. But yeah, a lot easier to assemble this than it was to cut all the wood and everything. So! This is your first shoot with me, right donnie?


Oh, nice!




Alright, moment of truth. Let’s see how many it did!

“How many’d you get?”

See how many it did!

OH NIIICE. NIICE. And it still has the round down in there! Dude! That is sick! So we’ve got one-two-three-four-five-SIX. I was close! Split the difference between me and Donnie. That is awesome. That is so sick!

It’s like eehhh will it go through all of them? I don’t know. And I still have the round there!

So this is one of those- this is one of those older tungsten rounds that game, with the Lahtis. The first one I had a misfire on, I had to take it and put it off to the side, those are always scary, because a lot of the older ammunition– oh look at my fingers from watermarking this wood here on the side, looks great, so clean.- So a lot of the older ammunition didn’t get sealed properly, or over time the seals would allow moisture to get in around the primer, so the powder could get wet, a lot of different factors could play into that stuff, but I ended up getting one of those tungsten rounds to go. I didn’t want to have to shoot some of the training ammo, because I didn’t think it would have as much of a punch as the armor-piercing rounds or the tungsten rounds. But that’s sick! That is awesome! And I have the round still! STILL!

Feel that, Donnie?


S’pretty warm, right?



“Could use that as one of those hand warmers.”


“Use it as a hand warmer!”





Oh you’ve got your ear pro off to the side. I was gonna say you’re a noob! You’re a noob, Donnie!

There’s one. There’s two. There’s three. Four. Gettin’ bigger. Heheheh that is awesome. Five. Six! Nice. We’ve got a liiittle bit of a dent on seven here. That round is sick. That’s awesome. That’s really cool. Little bit of a dent. I dig it!


Sources: Wikipedia, FullMag, Ultimate Weapon Facebook

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