This video was originally a two-parter, the first part showing the history
and the disassembly, and the second part out at the range.
However, YouTube now has problems with the machine gun footage on the range.
So I will not be publishing that here on YouTube.
However, I have compiled both videos together into a single longer one
that is available for free to watch over on Utreon.
If you take a look in the description text below, you can find a link to that video.
If you are on Floatplane you also have the full length video.
And if you are on Patreon you have received a link where you can watch the full-length version.
If you're not concerned about the shooting range section, then by all means carry on.
Otherwise check out the full video on Utreon. Thanks for watching.
Hi guys, thanks for tuning in to another video on ForgottenWeapons.com.
I'm Ian McCollum, and today we have the privilege
of taking a look at an extremely rare Finnish
sort of light machine gun. This is a Lahti L-33/39,
and it is the final evolution of Aimo Lahti's
air-cooled recoil-operated light machine gun.
This project originated in the early 1930s
when both the Finnish Army and the Finnish Air Force
had a requirement for a lightweight air-cooled machine gun.
Both organisations of course had lots of Maxim guns available,
but those are heavy and they're water cooled, and they're not really suitable
to things like being an observer's gun in the rear seat of an aircraft.
The Army also had some requirements for guns for things like
armoured car usage or anti-aircraft use
where having a water jacket and a condensing ... hose really weren't suitable.
Now when this design was requested, there was a limitation put on
the basic mechanics of the gun, and that was that it had to be a recoil-operated gun.
This is something that impacted the
Finnish Army's adoption of the LS-26 light machine gun as well.
Basically what happened is Army brass recognised that the Maxim gun,
which they really liked, which had done very good service, was recoil operated.
And therefore they decided that any other machine guns
adopted by the military should also be recoil operated.
If it was good for the Maxim, then it would be good for everything else.
Aimo Lahti of course was the predominant firearms designer in Finland at that time,
and he recognised that this ... fixation on recoil-operated mechanisms
was not really based in truth.
He would in fact develop the L-34 Sampo as a gas-operated light machine gun
that was far better than the LS-26, but was never able to get it adopted.
When it came to these aircraft and anti-aircraft machine guns,
he just accepted the limitation that was put on the design
and put together a gun that is actually very similar mechanically
in its core principles to the LS-26.
Now ... the first complete designs were in 1933,
and were designated the L-33, and that was an observer's gun.
And about 80 of those were made ... between like '33 and '35.
Between 1935 and 1937 there was another run of like 32 L-34 pilot guns.
All of these were being fed using this 75 round drum magazine.
And these guns, by the way, are chambered for 7.62x54, or in Finnish terminology 7.62x53mm.
There was then an interest in perhaps a wing-mounted aircraft gun.
So Lahti developed a belt-fed version of this that didn't really go into production.
There would be a 1936 pattern, so a 33/36, that was also developed.
That would have application to, say, armoured cars.
There was an infantry version that was prototyped but never put into production.
That had a pistol grip on it instead of these spade grips.
In total there were like a dozen different versions of this gun
that were prototyped, but only a couple of them went into production.
And none of them went into really large production.
This is the very last version, it's the L-33/39, and it was developed as an anti-aircraft gun.
So we have anti-aircraft sights on it, it went back to being drum fed.
And production of this was 136 guns.
All of these had a single serial number range,
these at the very end run from about 300 up to about 450.
So let's take a closer look at this, I'll show you how it operates
and how it actually works internally.
So to start off with, we have our markings on the back of the receiver here.
It is an L-33/39, an SA Finnish Army property stamp.
Manufacturer was VKT, the State Rifle Factory, and this is gun number 366.
All of the L-33 series appear to have been made in a single continuous serial number range,
I think starting at 100, these guns run between 300 and 450.
So now let's take a look at the actual controls.
We have a set of angled spade grips back here, nice and ergonomic, good to hang on to.
The two thumb triggers are right here, and there are a pair of safety levers in front of them.
So you use ... your index finger on the safety lever and thumbs on the triggers.
And these safeties simply prevent the trigger from going forward until you lift them up.
There's a little bit better view of a safety right there.
The charging handle is mounted on the bottom of the gun which is,
I think, a clever and effective way to do that for a gun like this.
For an observer's gun or a vehicular mounted gun,
this is going to be within easy reach all the time, and it doesn't interfere with the sights.
And it allows the gun to stay relatively narrow without anything sticking out the side.
This is a non-reciprocating charging handle, it has a locking lever here.
And then I can slide it forward, where it will lock into the bolt.
And then it's a fairly hefty recoil spring, but this (pull that back) locks the bolt open.
You can now see through the ejection port here that it's open.
And when you fire it - the bolt drops shut.
So the charging handle is readily and easily accessible down there.
The magazine catch is two part actually.
We have one here that's going to lock into the back of the magazine,
and then we also have this handle on top of the magazine.
This allows a gunner to stick their hand through
and retain control of the magazine even if the plane is manoeuvring.
And in order to release the mag you actually have to pull up on this handle.
You can see right there, there is a second magazine release
that unlocks it from this centre post.
So I push this one forward, squeeze that together,
and the magazine lifts nicely off. This holds 75 rounds.
There is a ratchet assembly on it here, which you have to lock open to load it.
So it's spring-loaded, we can push that pin up.
That allows me to lock the ratchet out so that I can load this.
It's ... a little tough without actually putting rounds in it.
Fairly similar to a Degtyarev drum. ... There we go. [There is a dedicated loading tool, which I don't have here.]
[There is a dedicated loading tool, which I don't have here.]
Anyway fairly similar to a Degtyarev drum where this centre ... piece stays in position,
and the top actually rotates as you're shooting, there's a big spring inside.
Unlike a Lewis gun, this magazine is spring powered, not mechanically powered by the gun.
We've got a trunnion block right here for mounting into a pintle.
This allows you a lot of flexibility of course for anti-aircraft use.
It feeds from the top, ejects out the side.
So first off, this is the only sight on the gun.
It's not set up for any sort of infantry iron sights down on the receiver or barrel jacket.
This is elevated to get ... high enough above the magazine.
And for anti-aircraft use you're really not worried about height over bore.
The sight itself gives you a rear post and a front spider web.
And the way these work is these give you an indication of lead for the aircraft.
Now this is set up so that I can loosen the front sight and adjust it
based on the speed of the aircraft, from 80 up to 200 kilometres per hour.
And that allows my leads to be accurate
Disassembly is done with this very Lahti-style pin.
You'll recognise this off of some of his other guns.
We're going to rotate that 90 degrees, so that it unlocks here.
Wiggle this out.
Now once this comes all the way out, the spade grip assembly is going to come off the back.
And it has the recoil spring under tension in there.
So I want to hold onto this when I get the pin out,
or else it will go spraying across the room, which is not a good thing.
There we go.
So there's our recoil spring.
And there is our spade grip assembly.
The actual sear is right down inside that socket.
You can't really see it here, but when I pull the trigger forward
it drops a sear in there which allows the gun to fire.
This fires from an open bolt, if that wasn't already clear.
Now I can pull the charging handle forward,
we can use that to pull back some of the internal components.
We have ... our bolt here, and call it our sort of [bolt carrier].
This is what's actually going to hang onto the sear inside the grip assembly.
So this nests over the recoil spring and locks down like that.
This is going to hold onto the firing pin, and drive it forward at the moment of firing.
This is our locking block right here.
But wait, there's more.
The whole bottom of the gun will pivot open and then ...
I can pull out ... the barrel.
Note that we have a booster surface up front as this is recoil operated.
And there's a booster up at the muzzle to help give it extra impetus to push this back upon firing.
The whole barrel is fluted.
And then we have this whole block, including an accelerator lever here.
Note that this is serial numbered to the gun, A336.
These guns actually came with a complete spare set of internals.
And we actually have the number two barrel here, which is marked B366.
Along with its bolt.
So with that opened up you can see that the
receiver shell here is basically just a big box that holds everything together.
OK. This is a little bit complicated on the inside, so let's strip some of the parts out.
We already took a look at the bolt. So we've got our locking block here,
and that is going to lock into this inside the receiver.
So, you can see the locking shoulder right there, it's kind of slightly different coloured.
And it is installed as a separate piece so that it can be heat treated properly.
We have a safety bar that runs in the receiver, right there.
That is going to run up and down.
We have an accelerator lever right here.
And then we have, let's call it our bolt carrier, right here.
So, ... when you fire, this is going to go all the way forward.
The bolt is going to hit the face of the chamber there and stop.
This piece, this bolt carrier below it continues forward.
It has a wedge that is going to push this locking block up, and then push the firing pin out.
So that's before firing, locks, and at the moment of firing the firing pin protrudes.
This, sitting in the receiver, is located here in this track.
And it is going to prevent this locking block from moving up
enough to allow the gun to fire, until it's fully in battery.
Once it is in battery, then we have a little bit of extra space here
that allows this block to lift up,
which allows (there we go) the locking block there to move up into position.
Now when this is all installed in the receiver.
We put that in first.
These slide in from the back.
And you can see ...
when this goes into battery that's going to lift up. And as I pull it back, that block drops.
When you fire, this whole casing is going to start moving backwards
inside the receiver assembly itself.
It's going to be pushed back by recoil,
as well as being pushed back by this face being pushed on by the muzzle booster.
As this starts to move back, the accelerator here (there we go),
the accelerator here is going to lock on to a surface in the bottom of the receiver, right there.
Which forces this to pivot, which is going to accelerate the bolt and bolt carrier rearward.
This is actually very similar to what's done in a Browning ... machine gun,
an accelerator to kick the bolt open.
As the bolt opens up, the locking block drops of course,
and then the whole thing can cycle backwards
until it has ... travelled far enough to kick the empty shell out.
You can see the ejector right there,
so it's going to kick the empty shell out right about at that point, right there.
And then as it cycles forward again it's going to
pick up a new round from the magazine, chamber it.
(This takes a little bit of effort.)
Chamber it, lock it, fire it, and the accelerator is ready to kick it open again.
Now what's cool is ... in addition to the gun and its original spare internal assembly,
we also have an original tool kit for this.
So if I open that box up.
We have everything you would need to work on the gun.
We've got pliers, wrench,
a list of parts that are in the kit.
We can lift this out.
Got a broken [shell] extractor, hammer, wrench, oil bottle,
small parts, pin punches, cleaning jags, spare mainspring for the gun.
This is a scraper for cleaning out the muzzle booster.
And all in its original case, which is a really neat accessory to have with something like this.
So as I said, production was very small on all of the different patterns.
This is the most common, but that's really a very low bar to clear for this pattern of gun.
These were actually tested by the United Kingdom in 1934, but nothing came of it.
And ... ultimately production of the 33/39
wouldn't come to its conclusion until after the end of the Continuation War.
By the time production began on these in 1941 the country was at war.
These were made by VKT as you saw, and VKT had a lot of other things on its plate,
and that significantly delayed delivery of these guns.
So that contributed to there being a small number of them.
The last ones weren't delivered until after the war.
They were however kept in service for a remarkably long time.
As of the late '80s, early '90s, the Finnish Coast Guard was still using these.
In fact it wasn't that long ago that they were still using these
as basically anti-aircraft guns mounted on small boats, small ships, small vessels.
So really a very cool compact design, cleverly built.
And really a privilege to get a chance to take a look at one.
Hopefully you guys enjoyed the video. Thanks for watching.
[ Shooting footage available free to view on Utreon. ]