Hi guys, thanks for tuning in to another video on ForgottenWeapons.com.
I'm Ian McCollum, and I am here today at Morphy's
with an absolute unicorn of a gun.
This is a British Sten Mark IV(S), or Mark IVA(S).
That is the suppressed version
of the prototype version of the paratrooper Sten gun.
So the British developed this in 1943 and 1944, looking for something
that would be more suitable to paratroops than the standard existing Sten Mark II and Mark III.
Now this is the even like rarer version than the regular gun, the suppressed version.
But normally this would have a barrel that would end right about here.
You've got a stock that folds over underneath like this.
And that gives you a really small compact package,
something that's really easy to stow in airborne kit
without having barrels and stocks and grips and stuff sticking out all over the place.
That was the concept. Execution wise: nyah, this thing's pretty much terrible.
But we'll get into that in a moment.
Essentially it is sort of a hybridised version of the Sten Mark II and the Sten Mark V.
In fact, let's just go ahead and take a closer look right now.
Alright, let's go ahead and start with the stock here, ... this is a terrible stock.
But in order to unlock it you pull this lever forward.
That is going to unlock this little latch right there.
And then we just pivot it around ...
like that, and it's going to lock into position extended.
Now notice the cheek weld you get here, which is no cheek weld,
your face just kind of floats here sitting behind the sights.
This is clearly not a precision sight-using sort of thing.
But it does have a better pistol grip than a standard Sten,
I will definitely give it that, but that's about the extent of it.
Now as for the rest of this, the magazine is a totally normal standard Sten magazine.
Magazine release is identical right here.
Really the only marking we have on here is "Sten Mark II",
because these were manufactured as conversions from existing Sten Mark IIs.
So that's why the magazine well is marked like that.
That appears to be a serial number 3, although
with pre-production stuff like this you kind of never really necessarily know.
Now the suppressor was originally held in place by either a rivet or a screw.
If I undo it one thread right there, you can see where it was originally held in place.
That rivet or screw is now gone, so I can go ahead and take the suppressor off.
Which I'm going to do because it's big and heavy and this will make it a lot easier.
Alright, you may want to hide your eyes for this frightening bit ...
right, oh my goodness, right there. OK, so.
Suppressor is off. The barrel on this is all of 3 inches long.
Now the ... standard Mark IVs also had very short barrels like this,
and they actually had sort of a conical flash hider on them
because of the amount of flash that would be created otherwise.
For the suppressed version, the flash hider is gone of course.
There are 6 vent holes drilled in the barrel, that's to help vent some gas out
and reduce the muzzle velocity in order to make it subsonic.
Because as long as it's subsonic the suppressor will be a lot more effective
because there won't be a sonic crack when you fire.
Now originally this expansion chamber here was filled with a roll of brass ... mesh,
which is gone now, but there was an expansion chamber there.
We then have the nose cap of the suppressor which we can take off.
The internals here are essentially identical to the Sten Mark II suppressed guns,
so I'm not going to further take the suppressor apart.
I do have a video on the Mark II(S).
If you're interested in more details about the suppressor, take a look at that video.
This thing probably did originally have some sort of padded handguard
to protect you from the heat of shooting, but it is long since gone.
There are a number of other mechanical changes here,
actually there's a lot more going on with this gun than you might initially expect.
So the stock of course is different, but then the whole receiver tube has been shortened.
If we compare this to a [Sten Mark I*], you can see that the receiver tube
is about an inch, 2 inches shorter on our paratrooper gun.
Also on the suppressed Mark IIs, which did see standard issue use,
the suppressor and barrel were a single unit that threaded into the receiver.
Here the ... rear thread, so basically the rear cap of the suppressor and the barrel,
are permanently affixed to the receiver. You can see a weld there holding the front sight in place
and holding the barrel nut here in place.
So that can't be interchanged on the Mark IV.
So geometrically the trigger had to move forward because of the pistol grip being in place here.
On the Mark II ... essentially your pistol grip is the wrist of the stock here.
So - it doesn't work quite that way.
But what they did was keep these two components,
the frame for the fire control group and the cover, they kept them the same
and compressed the trigger mechanism inside to fit in this shorter space.
The Sten Mark V has a similar issue with the pistol grip forcing the trigger to move forward.
But what the Mark V did was take this component right here and lengthen it.
So that the ... fire control geometry inside stays unchanged.
And you can see on the Mark V this cover plate goes all the way up
right to the magazine well component here, and they had to adjust that cover a little bit to fit it in.
On the Mark IIs that cover plate ends well before the magazine well.
Now on the Mark IVs they kind of did both.
So you can see that they've modified the cover plate here because it now is notched
so that it can extend over the magazine well.
And the whole thing's been compressed, so we'll take a look at that internally in just a moment.
But first let's go ahead and finish our disassembly here.
The buttstock comes off just like every other Sten gun,
so you push in the recoil spring, and the buttstock component is just going to come right off.
We can still pivot this guy, pull the spring back
and that just rotates around back and forth. There we go.
Then I'm going to go push this in, rotate it,
and then I can pull the end cap out, the spring out.
The bolt. It's worth pointing out the reference material says that
the Mark IV has a ... different style of bolt handle.
This one doesn't, this is a standard bolt handle.
So I don't know exactly what to tell you there except that with pre-production stuff,
experimental stuff like this, there are often exceptions and variations. There's our bolt.
Now because what we have is the suppressed Mark IV, there are a couple of other changes
that had to be made to it in order for it to run reliably suppressed.
Namely the recoil spring was shortened,
so here's a standard one, this has been cut down a couple of inches.
And the bolt has been lightened. So this is a standard bolt, it weighs in at about 21 ounces.
This is the Mark IV suppressed bolt, you can see they've wasp waisted it here.
They've taken about 4 ounces off, so this weighs 17 ounces, or about 20% less.
And the reason for this is that the short barrel and the barrel venting
reduces the energy of the projectile such that the standard bolt and recoil spring
would prove too hard for the gun to cycle.
Essentially it would no longer be fully reliable, it might short cycle.
By reducing the spring weight and the bolt weight,
you essentially bring the system back into balance with reduced power ammunition.
So you see these modifications on the suppressed Mark II guns as well, and the same thing here on the IV.
Now if we take a look at the fire control groups, here's our Mark IV, here is a standard Mark II.
And you can see the difference in the geometries.
So originally the trigger would have gone through this hole.
You can see that right here.
This pin is filling in for the pin right there that the trigger stops against.
And then of course the spring here is shortened.
The geometry is different, like they basically just had to mess around
with the geometry to fit everything into a smaller space.
And this is very much unique to the Mark IV.
The Mark Vs instead took this standard assembly and just lengthened this element
so the whole thing would fit, moved slightly forward.
In total about 2,000 of these were apparently manufactured between the Mark IVA
and the Mark IVB, and a couple of other even earlier prototype versions.
They never went into service. They were tested, they were evaluated.
They were never actually sent into the field into combat,
because the Sten Mark V was under development at the same time.
And the Sten Mark V was deemed a better gun and suitable to airborne use.
You see the nice thing about the Mark V is just like all of the others ...
you can ... take the buttstock off.
And now you've got a package that's basically as small as our Mark IV here,
but it has a really nice solid buttstock. It's quick and easy to put back together.
And this is very well suited to the airborne, certainly better than this horrible kludge.
So this ended up getting put into service, essentially all of the Mark IVs were destroyed.
There are a handful that survive today, almost entirely in British museums.
The Pattern Room has (well it used to be the Pattern Room, it's now the National Firearms Centre Collection)
has a couple of them, including a suppressed one just like this, which is really cool.
It's nice to have a second example, just to kind of prove out
that this is an original British suppressor. But the vast majority of the rest were destroyed.
This one's provenance dates to a US Marine Corps officer.
... Well, the stories differ, he told two different stories at different times.
One was that he was issued this for trials in the UK.
Later he came back and said, "No, I actually found it in a garbage pile at an American base in 1947."
Whatever happened, it ended up in the US. It was registered in the 1968 amnesty
and that makes it a fully transferable, curio and relic Sten Mark IV(S).
Almost certainly the only one of its kind in the US,
and one of what cannot be more than just a couple in private hands anywhere in the world.
So extremely cool to get a chance to take a look at this.
Hopefully you guys enjoyed the video. Thanks for watching.