Hi guys, thanks for tuning in to another video on ForgottenWeapons.com.
I'm Ian McCollum, and today we have a chance to take a look
at a very rare Russian World War Two machine gun.
This is a Degtyarev DS-39.
And they are very rare today
for reasons that we will get into in a moment.
And they exist pretty much only in Russia
and here in Finland.
So the origin of this gun goes back to the late 1920s,
when the Soviet Union decided to implement a program for a "universal" machine gun.
Now the people most famous for adopting a universal machine gun were,
of course, the Germans in World War Two with the MG 34 and the MG 42.
And the concept was a machine gun that could serve multiple different major roles.
It could be vehicle mounted, it could serve as an anti-aircraft gun,
it could be tripod mounted for the infantry,
and it could be bipod mounted and carried by a small two-man machine gun team.
Now the DS-39 would fulfil in theory three of these roles,
it was never set up to be a bipod-mounted gun.
But it was air cooled, instead of water cooled like the Maxim that was in Russian service at the time.
It was set up with its own tripod,
a relatively lightweight, compact tripod by the standards of the 1920s.
If you look at Maxim and Vickers gun tripods,
they are substantially more elaborate and heavier than this.
And this actually had, by the time it was put into production,
it had a dual rate of fire system where it could shoot either
600 rounds per minute for infantry use configured like this,
or 1,200 rounds per minute for anti-aircraft use where you want a higher rate of fire.
At any rate, the first prototype ... of this was delivered by Degtyarev in 1930.
And mechanically the gun borrowed a lot from his DP-27 pan-fed light machine gun.
Now there would be almost 10 years of development and iteration and testing of the gun.
So a few things changed, it went from a pistol grip to spade grips.
The most non-Degtyarev part of this, because the mechanism is very similar to the DP-27,
this has a Shpagin style of feed system.
Which we'll take a look at in more detail when we get up close on the gun.
But between '34 and '38 the Soviet Union actually bought a number of pre-production models,
they put it through testing, it seemed to be really good, it was working well for them.
And so it was formally adopted in 1939, went into production in June of 1940.
Which means it was in production in time to be equipping troops
that were going into Finland in what became the Winter War.
Finland would capture a bunch of these during the Winter War.
And before we talk about why this is such a rare gun today,
let's go ahead and pull it apart and show you how it actually works on the inside.
Alright, we'll look at a couple of parts here bit by bit. We'll start with the top cover.
We have a spring-loaded lever right there that allows us to pop this open.
Like I said, this is a Shpagin-type feed mechanism.
Very similar to what you would have in the DShK, also developed by Shpagin.
So when the gun is fired, you have a round in this claw here.
The action is going to open, that's going to pull this cartridge out of the belt
which will be sitting right there.
And we have sort of a rotational feed mechanism.
You can see that this pawl rotates [the next cartridge] up.
We have another set of feed pawls right here. So this is your belt release.
If you need to get the belt out
you have these two hooks right here, ...
depress this, lift those hooks up, get the belt back out.
So the one last element of the feed system is:
a cartridge is grabbed by the extractor claws right here,
but then it has to be pushed down to the firing pin position.
And that is done by this angled bar, which is also going to serve as the ejector.
It's a little hard to see here, but this has a curved profile to it.
And as the bolt travels backwards this bar pushes the cartridge down.
And ... there will be an empty cartridge having just fired down here.
The top cartridge coming down is going to push the bottom cartridge off,
very much like a Maxim gun.
The rear sight here is, of course, windage adjustable.
This is kind of like a Browning 1917 sight where adjusting this rotates the entire sight base.
And then lifting that sight up gives you graduations out to 2,900 metres.
The rear sight itself is a little U notch there.
You can see that the graduations go all the way down to 200 metres.
The front sight is an elevation adjustable round post
with a nice set of protector wings on it.
The trigger mechanism is of course a pair of spade grips with a pair of triggers, here and here.
And it also has a thumb safety on the right side.
So you have to lift this up in order to pull the trigger back.
On this side we have a threaded-in oiler bottle and brush.
And I think this one is still full of grease from the Winter War,
so we're going to leave that right where it was.
At the back of the grip assembly we have a recoil buffer here.
And that's going to absorb the last bit of energy from the bolt and carrier as they're recoiling.
Interestingly, this can be set for two different positions.
One when it's locked in, and one when it is unlocked and out.
Now the gun has two separate rates of fire,
600 rounds a minute for infantry use, 1,200 for anti-aircraft.
And that is ... changed through two different operations,
one of them is changing the position of this buffer.
And I believe in is the high rate of fire,
and out which provides less spring force on the buffer,
and thus less energy pushed back into the bolt carrier to go forward.
So I think in is anti-aircraft, and out is infantry use.
And then on the underside of the gas block we also have an adjustment right here.
That gives us two separate positions for the gas port.
And on this one I'll be honest, I have no idea which is which.
But one of those is a large gas port for anti-aircraft use,
I suspect it's this one, because it would be easier to bump that thing back in.
And most of the time you're going to want the lower infantry rate of fire.
There is also a pivoting carry handle on the barrel.
With the somewhat interesting feature that you can actually
flip the handle forward or backward, whichever suits you.
One of the rather unique features on this is the location of the recoil spring,
which almost takes a cue from the Maxim.
This tube right here is the main spring.
So I can take this and, in theory, pull it back ... there we go.
I can pull that out and you can see our spring in here.
And then this cutaway path is for this spring lug right there,
which is going to cycle back and forth as the gun operates.
So the first step in disassembly is to pull off the recoil spring.
The next step is to pull out this cross pin.
It's a little locking pin there.
Alright, with the bolt forward we can then pull the spade grip assembly simply off the bottom.
You can see the trigger operates this little lever right here.
We'll get to what that actually does in a moment.
There is your recoil buffer.
Next up we remove basically the fire control parts.
So the actual trigger mechanism is contained in here,
which is also, by the way, the part that contains the rear connection to the tripod.
So ... we'll pull the pin out.
And then we can take this, and it's on rails on the bottom of the receiver.
We can pull that out.
And then using the bolt handle, we can pull the bolt and operating rod out.
Alright, so here are our main components.
Aside from the spade grip,
these guys will look very familiar to anyone who's
familiar with the Degtyarev light machine gun.
There is no semi-auto functionality on the gun, it is simply safe or full-auto.
In addition to the thumb safety, there is also a manual safety here.
This is set to fire, that's set to safe, and that just simply locks the trigger from working.
So the way the trigger actually functions
is the bar on the back of the spade grips is going to push up on this,
which pulls down on that sear.
Pretty simple and very similar to the DP-27.
And then again, in the same sort of fashion we have our operating rod.
Gas piston at the front, with a bolt back here.
There is a hook on the back of the bolt carrier
that holds the firing pin extension, right there.
And this is locked by means of two flaps
(oops, which, just like the other Degtyarevs, fall off).
So the firing pin is used as the wedge that locks the flaps in place.
So when this all goes forward (of course this hook right here is controlling the firing pin),
when it's fully in battery that pushes forward which splits these two ... flaps apart.
They lock into recesses in the receiver, and then the gun is able to fire.
There is a front portion of the firing pin, right there, that is spring loaded.
And at the end of the forward travel of the bolt carrier
that's going to fire. So this fires from an open bolt.
We can pull these two out.
And then the firing pin extension comes out.
You can see we have the two claws for extracting a cartridge from the belt.
These ... have got to be tricky to make.
Spring steel, it has to be tight enough to hold the cartridge,
but loose enough to actually be able to snap over a new cartridge.
There is also an accelerator lever here,
which is an interesting addition that we don't see on the Degtyarev light guns.
And the way this works is (let's see, there we go),
when the bolt carrier is in position, when this all goes forward,
the bolt carrier will hit its forward travel and stop.
The bolt is all the way back when it's locked.
And you can see the accelerator lever right here.
When this fires the bolt carrier will travel backwards,
and it's going to hit right there, hit the accelerator lever.
Which is going to give the bolt itself an extra kick open.
And that is both probably what makes it reliable
and also what contributes to its most significant problem, which we'll touch on in a moment.
In total, Finland would capture 175 of these and put them back into service.
In 1943, VKT, the state rifle factory in Finland,
came up with like an eight-part rebuilding program
to try and ... fix some of the problems with the design.
It's unclear exactly how successful those were, but they did rebuild the guns
and put them back into service during the Continuation War.
At the end of the Continuation War there were I think
151 that were still in Finnish military inventory.
And they would actually stay there until 1986 before they were finally disposed of as surplus.
Now on the Russian side, production ended almost exactly a year after it began, in June of 1941.
And there were a grand total of 10,345 of these machine guns manufactured.
And the reason is while it seemed to do very well in testing,
it did quite poorly in actual field use.
The two particular issues that are described in the literature,
and specifically here my reference is Bolotin.
The two problems he references are, first off,
out of battery detonations which are a significant problem.
And the second is the extraction stroke being so violent,
especially with the accelerator that we saw in there,
that it would tend to pull the cartridge case out of the belt but leave the bullet in place.
This was a particular problem when you were shooting heavy ball ammunition.
And obviously that's a very substantial malfunction that
you just don't want to have to deal with when it's freezing and you're getting shot at.
... Obviously there was a program in Russia to try and figure out what was causing these issues,
and how do we rebuild the gun and make it more useful, you know, improve it.
Ultimately the decision was made that there just was no really practical way to fix the DS-39,
hence it was pulled from production in June of 1941.
The same machine gun program continued,
and eventually the result would be the SG-43 Goryunov [being] adopted.
Which shares ... a very similar configuration to this.
It is an air cooled, belt fed, sort of universal/medium machine gun.
Similar in overall concept to, say, the Browning 1919s.
At any rate, as a result of the very short production timeline
and the many field problems, these things are extremely rare to find today.
And it's very cool to have a chance to take a look at this one.
Hopefully you guys enjoyed the video.
Thanks for watching.