Hi guys, thanks for tuning in to another
video on ForgottenWeapons.com. I'm Ian McCollum, I am here today at the Royal
Armouries, the National Firearms Centre in Leeds, England. I'm here courtesy of ARES, Armament Research Services. Today we are taking a look at a very cool one of a
kind British post-World War Two light machine gun. This is the Korsac light machine gun,
also known as the EM-1, although that designation would
later be applied to a different rifle. Which we're also going to
take a look at while we're here. But, what's interesting about this is it was
designed by actually a Polish émigré firearms designer. Of course when Germany occupied Poland
a lot of people escaped from the country. And there were a number of Polish firearms
designers, quite talented Polish firearms designers, who made their way to the UK and
got to work designing firearms there. It wasn't just Polish, but Poles among others. Well Korsac right at the end of World War Two
got his hands on some German FG-42 rifles, and basically copied them in a bullpup
configuration. And that's what this rifle largely is. It's chambered for 8mm Mauser and it's
basically a bullpup FG-42, which is extremely cool. Now we have a second pattern FG-42 here
that we are going to use as a comparison, because we're going to go ahead and pull this apart, and take
a look at just how closely its parts ... compare to the real FG-42. A little bit of background on this rifle,
there's not a whole lot to say. Development began in 1945 and the project was
terminated in 1947, relegated to museum status. A total of 2,500 pounds sterling were put into
this effort and there were only two guns made. There was one that was in the white, and
there was one that was in firing condition. And this is the firing condition gun, and it
definitely shows some wear on some of the parts. The reason that the project was
terminated was there were several other projects along these lines, bullpup rifle projects, at
Enfield at that time that were clearly progressing better. And so they looked at this one, they said, "Well, we don't
really think this is ultimately going to be a successful project. So we're going to cut this off and
we'll continue working on some others." And this would definitely contribute some important
lessons towards what would become the Janson EM-2 rifle, which would eventually, for a very short
time, be adopted as British Rifle Number 9. With all that in mind, let's take a closer
look at this, and then let's pull it apart. The Korsac rifle here weighs in
at 11.5 pounds, that's 5.1 kilos. And has a remarkably long barrel of
course because it is a bullpup design. I don't believe this is the original magazine, but it took
magazines that were basically of the 7.92 Bren variety, which means ZB-26 magazines. And apparently the
magazine held 18 rounds, where the ZB magazines held 20. A lot of elements on this rifle were copied either loosely
or very strictly from the FG-42, the sights included. These are folding sights, just like on an FG-42. Let's take a closer look at
the controls on the other side. Alright, for reference sake here is an
actual FG-42. This has a safe and fire lever, and then it has a single shot and a full-auto switch. And in order to switch from single to
full-auto you actually have to lift this pin up against spring tension, and then rotate
it around. So that was the FG-42 set of controls. And the Korsac here is identical.
We have a safe and fire lever. And then we have single shot and full-auto. And this again is a spring-loaded plunger that
you have to lift up to move back and forth. Now on the FG-42 if you are in semi-auto
mode, the gun fires from a closed bolt. If I switch to full-auto, like that,
now the gun fires from an open bolt. Predictably the Korsac works the same way. So right now if I lock this open, I'm on
full-auto so it fires from an open bolt, like so. If I switch it to semi-auto it no longer locks open, because it
is now set to fire from a closed bolt. Disassembly of the Korsac is
going to begin at the rear end here. ... The butt plate has this spring-loaded button on it, going to push that in, and then rotate the butt plate
down about 30 degrees, and then it comes out along with its very long recoil spring. We have a series of ... interrupted threads right here
that lock the butt plate into the back of the receiver. With that out, we can now pull the bolt and bolt carrier
assembly out of the gun. I'm going to push this back. ... When you first push the bolt, you're actually unlocking the bolt and
cocking the firing pin spring, right there, and then it becomes nice and loose.
... Pull that all the way to the back. The charging handle then comes out, and it's interesting
to note that the charging handle has this little notch in it into which the plug on the
end of the recoil spring fits and it's this plug that prevents the
charging handle from coming out. So once you take the spring out and its guide plug at
the end, the charging handle can just fall out of the gun. Now we can pull this out the rear. There is our bolt and piston assembly. We're going to take off the trigger mechanism,
we're going to do that by removing this pin. You might expect that the pistol grip
itself comes off, but it actually does not. Once that pin is out then this trigger assembly and front grip comes off. And we have our two sears there.
So there's our semi-auto sear, and when I move this, now I have a full-auto sear. Next up, one of the cool features of the Korsac is that
the barrel is actually based on like a Bren gun barrel, and the whole thing comes out of the
receiver. So I can rotate the gas block here, wiggle this a bit, and our entire barrel assembly comes out, leaving us with
(oh, and this, we'll get to this in a moment), and there is our receiver. Being able to have the barrel separate makes
the receiver much easier to manufacture, because you can basically drill all the way
through everything, instead of having to have it blind at one end where the barrel locks in. One more bit to take a closer
look at here is the bolt assembly. This is very much like an FG-42,
we'll compare them in just a moment, but first I'm going to go ahead and disassemble this. And I do that by taking this rear assembly,
and I'm going to rotate it over to this side. There are a pair of cutouts right here
where this rear piece can come off, like that. Then the firing pin spring can come out. (There we go.) And then the [op rod] has
a little claw that holds onto the firing pin, ... I'm sorry, the op rod has a claw. Pull the op rod off, and the firing pin can come
out the back of the bolt, and there is our bolt body. Here we have a set of FG-42 parts,
and the Korsac EM-1 parts. And you can see all of these little
features are the same. For example, we have this pin in the end of the recoil
spring that locks the charging handle in place. That's the same on the FG-42, there's a little cutout
here that fits the plug on the end of the recoil spring. This was actually something that was updated
throughout the development of the FG-42. Early rifles did not have that, they just
relied on friction instead of having a cutout. And that led to charging handles kind of flying
out of the gun intermittently, which was a problem. And then these both share this
rather unique system where the op rod, the piston and op rod, have this
claw that holds the firing pin fixed in position. And it leads to a rather unusual mechanism of firing where
the sear is actually holding this slightly back inside the bolt. When you pull the trigger, this entire assembly
jumps forward maybe half an inch to fire, because the firing pin is fixed like this. So when these guns are operating, this is the
unlocked position with the bolt lugs vertical. And as this goes forward this
cam track forces the bolt to rotate, and it's going to sit in approximately this
position when it's cocked and ready to fire. And that means the bolt is locked in place, but
the firing pin doesn't extend through the bolt face. Then when you pull the trigger the bolt
is already locked in place, it doesn't move, but the recoil spring is pushing on the
gas piston and it snaps forward like that, and the firing pin protrudes through
the bolt face and fires the cartridge. Now these fire from, as you saw,
the open bolt when they are in full-auto, which means that this whole assembly is held in a
rearward position like this, unlocked and totally open. When you pull the trigger at this point,
this whole assembly goes forward and again the breech face is going to
hit the barrel, that stops the bolt, forces this to rotate. But on a full-auto
position nothing stops the bolt in this position, and instead it goes all the
way forward like that, fires, and then gas pressure on the head of the
piston forces the whole thing to cycle open again. One curious thing to note here, and I don't think
it's of any particular functional significance, is that the FG-42 here and the Korsac
the bolts rotate in opposite directions. And you can see that from the
mirror image cam tracks in them. So ... let's see, they're both going to be open like this and the FG-42 is going to rotate clockwise,
the Korsac rotates counter-clockwise. But that's about the biggest
mechanical difference between these two. Alright, now the Korsac is a bullpup, so we are
going to have to change the design a little bit. This can't just be a straight copy of the FG-42,
and the reason is the trigger mechanism. On the FG the trigger is basically right below the chamber, and so the two sear locations can
be located on the operating rod itself. The bolt is sitting right here, and so the semi-auto sear
can be right underneath the bolt and everything works nicely. On a bullpup you have to have a way to transmit
the trigger action back to the actual sear which is going to be back in here somewhere. The way they do that is with
this interesting sliding block. Now this is set up so that the gas piston fits
in here, and it actually has a matching slot so that the charging handle
locks these two together. (If I line them up correctly,) So the charging handle locks the bolt to this sliding bar by
way of the gas piston, and this is going to cycle all together. Now on the bottom of this we have a sear notch at
the front, and we have this sear notch at the bottom. And those interact with the
two sears in the trigger group. This sliding bar is going to act as the sear
catch, so in the ... full-auto mode right here, you can see that the sear is
hooking on the front of this bar. When I pull the trigger that sear is going to drop and
allows the bar past. If we switch to semi-auto mode we have now lifted up this, the right hand semi-
auto sear, which is going to catch in this track. Of course that track allows the bolt to come almost all the way closed, like this,
before it drops and allows the last bit of forward travel like that. Now they did find in testing that in
semi-auto this gun wouldn't reliably fire. There just wasn't quite enough spring pressure left in that little bit of forward travel
to actually set off a primer. Now it did work well in full-auto, because of
course in full-auto you are starting way back here. You've got a lot of time to build up the full
momentum from the spring being fully compressed. So it may have been partly that that led
them to scrapping this project in favour of what would become the other
EM-1, and then the EM-2 rifle. So the barrel assembly here has a set of Bren style locking
interrupted threads on the back, which we can see there. And then you can see that there are two
angled surfaces cut, one here, and one here. And those are the surfaces that are going to force
the bolt to start rotating into its locked position inside this area. So these are going to match up with
the locking lugs inside the receiver. We have a gas block here
at the midpoint of the barrel, and that is actually going to run a short little tappet
style piston. That's going to come back when the rifle fires, and impact on the front of the op
rod here to push that backwards. It does appear to have been adjustable with two different
positions. Although I don't know exactly what the two positions are. Presumably two slightly different sized gas apertures. And then in the front we have our folding front
sight, a small conical flash hider, and bipod legs. I have to say this is not one of the most
confidence inspiring bipods I've ever seen. Its legs are very close together, which
wouldn't make it particularly stable. The locking system in the field would
be considered completely too flimsy. But of course this is a prototype sort of gun, and had it obviously gone into
production they would have improved that. It does also have a bayonet lug under here,
interesting to note. So you could fit this with a bayonet. Now if we consider production of this gun, ... one of the things
that's going to occur to people with manufacturing backgrounds is, "Holy cow, you have to cut interrupted threads for the
barrel here, right smack in the middle of this long receiver. And that is going to be ... basically
an impossible job. To get a tool head that's this long to come in here, and then
accurately cut ... interrupted threads for the barrel." However, if we look closely, we can see that there's
a seam line right in front of the rear sight, right there. So this was actually manufactured in two pieces. You have the front half of the receiver here, which is all just hollow tube basically, pretty easy to to drill out. And then you had a somewhat
more complex piece back here, but you could drill the small holes for the
gas piston and the bolt assembly in the back, and then you could drill out the big
hole for the locking assembly in the front, and then you would take a separately machined
interrupted thread nut, basically, press it in here, and then weld the front of the receiver on. And
I'm pretty sure that's how this was manufactured. They did a really good job of it though,
and it's a nice, very small, clean little seam. Well, there is in fact only one of these rifles in existence, and
it's very cool to have been able to take a close look at this one. I love looking at the the history of where these
German World War Two designs ended up going. And this is only one of several German mechanisms
... where the development was continued by the British after World War Two leading
to other newer and cooler guns. So I'd like to give a big thank you to the National
Firearms Centre for allowing me to take a look and pull apart this extraordinarily
cool Korsac light machine gun. Their collection is not open to the public, but it is
available by appointment to small arms researchers, so you can call them up and
arrange to schedule a visit for yourself. Or right now you can head over to Armament Research
Service's website, take a look at their blog, the Hoplite, and they will be posting close-up high-definition
pictures of this rifle as the video goes up. Thanks for watching.
