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20mm Lahti L39 Antitank Rifle (Shooting & History)


Fun? Oh yeah. Hi guys, thanks for tuning in to another
video on ForgottenWeapons.com. I’m Ian, I am of course here today at the James Julia Auction Company, taking a look at some of the guns and cannons that they are going to be selling in their October of [2016] firearms auction. Now we’ve got this one outside right now because it is an absolute behemoth of a gun, and because we’re actually going to do some shooting with it. And I figured if we’re going to drag it out to the range, I don’t want to have to drag it into the photo studio. Now, this is a Lahti L39 20mm anti-tank cannon. This is a type of firearm that was popular in … almost
all of the major European militaries in the 1930s. But it’s a type of gun that became obsolete almost
immediately upon the beginning of World War Two. So the idea was in the early ’30s, and even
into the mid ’30s, a lot of the mainline tanks were actually quite lightly armoured. Light enough
that you could build a really big rifle like this, and have a one or a two man crew that could actually
carry the thing around and destroy enemy tanks. And it’s really cheap. You know, this is an expensive
gun to make, but compared to a tank, it’s super cheap. This was a really cost-effective way to fight
an enemy that had a lot of armoured vehicles. So that was the idea. The British had the Boys
anti-tank rifle, the Germans had the Panzerbüchse 39, the Americans never really had one, the Poles
had one. A lot of different people had these things. And the Finns are a little bit unusual in that they
actually opted for 20mm, instead of what was normally about a .50 (well in the German
case a very high velocity 8mm round), but normally these were .50 calibre cartridges used. As a matter of fact, when these guns were
being designed and developed there was a lot of argument within the the Finnish military
and bureaucracy about what cartridge to use. And the designer, a guy named Aimo Lahti
(who was like the John Browning of Finland, he designed pretty much all
of the major Finnish firearms), he was really arguing for a 13.2mm cartridge, and
they did a lot of testing with that as well as 20mm. And the argument for 20mm was a lot of people
who wanted … to use the same ammunition, and possibly the same guns, for both anti-tank and
anti-aircraft purposes. Which makes sense logistically, but there were questions about well,
you know, if you have a smaller projectile you can give it a nice hard armour-
piercing core and get it going faster. Whereas a larger projectile you
could have an explosive payload. Ultimately Lahti lost out and they decided to
adopt the 20mm version of the gun, which he dutifully built (and did a gorgeous
job of it, these are fantastic guns). The gun was formally adopted in September of 1939, and
then the Russians promptly invaded in November of 1939. And that was the Winter War, and these guns
were not available. In total … there were two prototypes in … a slightly smaller version of the
cartridge, I believe it was 20x102mm (or 113mm?). It was an early prototype cartridge,
prototype rifle. Those two guns were actually used in the Winter War
pretty effectively, but that’s it. As the Winter War was concluding, these things really went
into production because this was a very high-priority project for the Finns. They didn’t really have a lot of
tanks and the Russians, by golly, had a lot of tanks. Unfortunately by the time the Continuation War picked
up, the Russian tanks were things like T-34s and KVs that were too heavily armoured to
really care about something like this. So these were used extensively in the Continuation
War. They had, you’ll see most sources say like 1,750 or 1,800, a little less
than 2,000 of these guns. But I’m aware of a picture of one that
has a serial number that’s, like 2,600. So maybe there were a few more, it’s hard to say. But during the Continuation War they were primarily
used as … a combination between a long-range sniping rifle and a long-range anti-materiel rifle.
While these couldn’t take out a tank’s armour, they could do things like shoot through the ports on a bunker, or you could shoot up an enemy machine-
gun nest with these at pretty long range. They have fixed barrels, they’re gas-operated semi-
automatic guns, and they were found to be really quite accurate. Now I know people are going to ask if they put
scopes on them. No, they never put scopes on them. They have iron sights. But the Finns
were really good shots with iron sights, and didn’t necessarily need scopes
to do good work with something like this. So the cartridge that this uses is
the 20mmx138B, it’s a belted case, typically called the 20mm Solothurn Long. And it
was a common cartridge at the time, actually. It’s the same cartridge that was used in
the Solothurn S-18/1000 anti-tank rifles, and, in much greater numbers, it was
used in the German Flak 30 and Flak 38, which were the single barrel and quad-
barrel anti-aircraft guns. So as the Finnish bureaucracy had wanted, this actually was
a cartridge that was used for both anti-tank and anti-aircraft purposes. In fact, by
1944 they would develop a full-auto version of this gun, fired from
a mount, for anti-aircraft use. Different types of projectiles were available for these.
We’re going to be shooting dummy training rounds today, they’re just inert, solid bullets. But they
also had armour-piercing, armour-piercing tracer, they had phosphorus incendiary rounds, they
had high-explosive rounds, all sorts of fun stuff. In fact, one account I read said that during
the Continuation War one of the things that Finnish soldiers would do from time
to time, is take some of those incendiary phosphorus rounds and crank the guns
up to a really high angle of elevation, and lob some phosphorus projectiles over as far behind
the Russian lines as they could to try and start forest fires. Just, you know, to be obnoxious. So there are a couple unusual
elements to the operation of this gun. It has a 10 round magazine,
which we’ll load up in a minute. It has a crank style of bolt handle because the
recoil impulse from this is so significant that if you were just to try and pull the recoil spring back,
really no normal human could. So instead there’s a ratcheting crank handle that you
turn to open the bolt. And while it’s semi-automatic, the gun actually locks open
after every shot is fired. Probably to help cool and … I don’t know, it’s an unusual
system you don’t really see elsewhere. There’s a grip safety, and what happens is when
you depress the grip safety it releases the bolt. So when you’re ready to shoot, get in
position, grab the grip safety, the bolt drops, and then when you’re ready,
you pull the trigger and fire. One thing we’re going to have to be very careful of,
and this is important for everyone out there who owns Lahtis (because there’s actually a
substantial number of these out there, and there is ammo, and they do get fired), do not
put your hand in front of that trigger guard. That’s a big hefty trigger guard, and it is there because
these cases will eject pretty much straight backwards, and if you put your hand in front of that trigger guard you are literally going to lose fingers
that are crushed by the ejecting case. This is something that has happened to at
least a couple of people who didn’t know better. And you really want to avoid that,
that will definitely ruin your shooting day. So, keeping that in mind, I think it’s about
time we did a little bit of shooting with this. Oh, I should point out, it has a dual type mount. They’ve
got skis there for when you’re on soft ground or snow, you know, not that there’s ever
really soft snow in Finland in the winter. And then if you’re not on soft ground, there are
bipods with some nice pointy feet on them. So we’re going to be shooting it from the bipod
today because we’ve got some nice hard ground to stick that into, and that’ll prevent this
from actually sliding backwards under recoil. Because … the different types of projectiles
obviously ranged from like 1,800 grain up to 2,500 grain, that’s on the order of what, 120 to, I want to say
140 gram projectiles, with muzzle velocities of 2,600 to 3,000 feet per second, so 800
to 900 meters per second. This generates 35,000 foot-pounds of muzzle energy, which
is approximately three times that of a .50 BMG. So that’s why it weighs 109 pounds. When this was carried it was actually
typically carried by a two-man team, and you’ll see pictures of guys carting these around. Obviously they’d throw them
on a truck any opportunity they had. But if not, you get one guy carrying the barrel
and you get one guy carrying the stock end. Alright, enough of that. Let’s do some shooting. So the first thing to do when
you’re getting ready to shoot a Lahti, just don’t forget to take the muzzle
cover off. A little spring tab here, just hangs by its chain. If you forget to do that,
you’re going to get this really cool one time thing where you blow this muzzle cover downrange.
But then you’re going to have to find another one. So take that off. Next up we have some basic operation of the gun.
We’re going to start by opening the dust cover, that’s just held in place by the magazine
catch, keeps junk from getting into the gun. Right now the bolt is open, so I’m going to
run you through the operating process here. While this is semi-auto, it does lock open after every shot, and to release the bolt you depress the grip safety … kachunk. Once that has been depressed, you hold it
down, and when you pull the trigger, it fires. Now if you want to manually open the bolt,
you have this crank handle. This is like the world’s most ballistic crossbow ever. Push that in
to unlock it, and then two full revolutions or so, lock the bolt open, release the crank handle, and now you’re good to go We have iron sights here, they go from 200 yards up to
1,400 yards. The front sight’s way out on the barrel there. And that’s pretty much it. You will notice
there is a little rubber buffer wheel here, that’s because that’s where this brass is getting ejected. So again, don’t put your hand here. Don’t do it.
Put your hand up on the back somewhere. Last bit of prep work, once you’re in position.
This is the manual safety, this is the fire position, that’s the safe position. It just disengages the trigger. So here’s our 10 round magazine. The Lahti
very thoughtfully comes with a loading tool, this one’s in the spare parts kit that comes with this gun. What this does is simply allow
you to manually depress the follower, and then we can slide the cartridge in, like that, slide it all the way back. Repeat that 9 more
times and you have a fully loaded magazine. There is a little viewing strip here so
you can see how many rounds you’ve got. I’m going to leave that at one for our first shot. All righty, here we go. Open the bolt. No hand in front of the trigger guard. Here we go. Hehe, let’s do some more. All right, we’re ready to go with the second
shot here. I’m shooting kind of downhill, so I actually have to lift the back end of
the gun up higher than you normally would. Close the bolt and we’re ready to go. These are really fun. And I think we set off the car alarms again. We gave
them just enough time to shut up and now they’re back. Ah yeah! One thing I noticed reviewing the high
speed on this is that the brass is actually bouncing off of this rubber buffer,
which is clearly what it was put there for. I believe not all of the guns actually have
those, so be aware and even with that buffer I’m not putting my hand anywhere near the front of
this thing. I do not want to get hit by that ejected case. Well, thanks for watching guys, I hope you enjoyed
the video. This thing was a lot of fun to shoot. And it is of course coming up for sale here. You used to be able to buy these in the ’60s out of
magazines, and so a lot of them actually got purchased. And they’re on the market now and they’re guns like this. This one in particular comes with
the original humongous wooden crate. It’s got … I believe four cases of magazines, two
mags each, so you got eight magazines for the thing. It comes with a bunch of
ammunition already loaded and ready to go. And, well as you can see, it’s a
tremendously fun thing to shoot. So if you’re interested in it, take a look
at the description text below this video, you’ll find a link there to the
James Julia catalogue page on the gun. You can check out their pictures and their
description. And then go back, watch the shooting footage again, and call them up to place a bid, or come
up here to Maine and participate in the auction live. Thanks for watching.

100 thoughts on “20mm Lahti L39 Antitank Rifle (Shooting & History)

  1. Hauskanen opetusvideo!

    Älä laita sormeasi tänne äläkä tee sitä ainakaan kovin useasti…
    Ihankuin monellakin ois moisia aseita kotonasa varastossa ihan helposti käyttöä varten.heheh
    Sotaa odotellessa. .

  2. That's a hell of a way to deliver a quarter pounder with cheese 🤪
    P.S. I think I've heard guns firing quieter than that thing chambering.

  3. Is it just me, or did the firing at the beginning of the video sound more like a rocket launcher than a rifle?

  4. does this remind anyone of the gauss rifle form fallout 3 and new Vegas with the crank and general look from the receiver

  5. You don't need a scope when you know how to shoot.
    Put one of these in my hands…
    🖖🏻🇫🇷😎🇫🇷😇🇫🇷🖖🏻

  6. Compare it with the Polish 20 mm Extra-Haevy Machine Gun…fully automatic, using same cartridge and was already used in Semtember 39 …killing several German tanks as mounted also on the TKS tankette. I have an impression, the Polish design was simpler and better.

  7. I didn't enjoy watching you hastily shoot dirt with poor fundamentals. I'm not an enthusiast or sub, just a soldier passing by laughing at you.

  8. Commander: You see that vehicle over there, soldier?
    Soldier: Yessir.
    C.: I don’t want to.
    S.: Very well, sir…
    ka-chunk
    BOOM

    Target has left the chat

  9. In Finland they eat iron, poop chain, love Sauna and make guns with skis that recoil on bringing the bolt forward! That's just too badass! 🇫🇮

  10. 4:29

    Given the deadliest sniper in the history of warfare, Simo Hayha was Finnish and famously only used Iron Sights, I'd say that's an understatement.

  11. Why the hell did they even include a dust cover ??? I'm not Finnish, but I'm willing to bet there's not a whole lot of dust blowing around in frozen tundra wintery conditions like you have in Finland, Northern Canada, or Russia where summer is only like a month long

  12. When tanks come to close, just sit backwards on this beast, hit the trigger and the recoil will boot ya back home

  13. This gun was effectively used during Winter war against T-26. During Countinioution war it was just a peace of crap. Can make nothing against T-34 or KV

  14. This model comes all ready for the Biathlon. Good thing with this is that you don't have to ski anywhere at all, you can just stay at the starting line and annihilate the targets from there.

  15. 🌈Хороша! Из такой можно для ужина ФАРША настрелять или паштета. 👏👏👏

  16. feel like everytime there's a warning that involves some aspect of the gun applying a huge amount of force (e.g. the ejecting case on the Lahti), there should be a piece of wood placed in the way of it to demonstrate how damaging that force would be.

  17. Really, you had to point it out that automatic version is on a MOUNT? Man, someone tried to shoot the automatic version without a mount and he could next fetch his shoulder from Petrograd.

  18. Anyone notice the slow motion shot at 11:20
    The bullet goes straight down with such force and at just the right angle that it kicked a bunch of dirt straight upwards into the gun, can’t be a good thing

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