Hi guys, thanks for tuning in to another video on ForgottenWeapons.com
I'm Ian,
I'm here today at the Institute of Military Technology, taking a look at some of the interesting firearms that they have in reference collection here.
Today, we're going to be taking a look at the German MP38 and MP40,
because there are a couple of differences between these guns and I think a lot of people probably don't know what those differences are or why
So the MP38
was the first submachine gun really formally, on a large scale, adopted by the German military
It was based on the Erma MP36 prototypes which were pretty heavily based on Schmeiser patents
So the design traits of this gun actually really go back to the MP18 from World War One.
The bolts of these guns and the MP18 are very very similar and the
magazines are also quite similar, in fact that's one of their weak points, is the magazine for the MP38 and 40 and by the
way the magazines are interchangeable and identical for the 38 and the 40.
Those magazines are a carry over from the MP18, they are a double-stack, single-feed magazine.
Which is, it's simpler to design a gun around because there's only one position that a cartridge comes into. I should specify: single feed
means that the cartridges taper into a single stack at the top
and there's only one cartridge sitting at the top of the magazine that can feed
A double feed magazine is one where two cartridges come up side-by-side
This one will feed and then this one's on top and it feeds and then next one
The advantage of a double feed magazine is that it is, there's less friction
because you're not trying to take the stack of cartridges and compress them into a single stack
That also means that they're more reliable to shoot, they require a little less spring tension, it also means
they're a lot easier to load especially if you don't have a special loading tool.
So double feed is better,
but single feed is what they'd used on the MP18 and that design just carried over into the MP38 and MP40
Anyway, I digress
So the design
came through Erma, they did some testing on the MP36, they ended up adopting it in the form of the MP38 in
July of 1938. They only made a thousand of them in 38, and then production ramped up until it finally ended in
1942, they had a total of about 42200 (forty two thousand two hundred)
MP-38s manufactured and by the time those were done they had transitioned to the MP40. Now the
differences between these two guns are not mechanical at all, really, they are
industrial, so what they did was they took the MP38 which has,
interestingly it's a tube receiver submachine gun, but it's an entirely machined receiver. So they took a piece of bar stock
drilled out the middle and then machined down the outside and added this fluting in to reduce weight
There's an incredibly expensive way to build a gun like that and with the MP40
they realized wow, you know we can do this a lot more simply and a lot cheaper
by maybe using a stamped sheet metal tube, so that's the primary difference between the 38 in the 40s.
The 38 is a milled gun, the 40 is just a stamped tube.
Now that carried over to some of the other parts as well
You can see that
We have a smooth sided magazine well here with hole in the middle to reduce weight. They decided the hole wasn't worth the trouble
so on the early MP40s, they just went to the smooth-sided magazine well. On the late MP40s
they decided they can make the metal thinner and stamp some ribs in it for reinforcing to make up for it
So,
simplifications followed within the MP40
so a bunch of changes from 38 to 40 and then some smaller changes as the war progressed
Pretty much every country, but especially Germany and also Japan
simplified their guns as the war progressed because the economy tightened up, they needed to be able to produce more stuff with less material
All right now there are some other smaller details that did change so why don't we take a closer look at each of these three
progressing guns and I'll show you the small details.
So we've grown accustomed to thinking of the MP40 as a second-generation
stamped metal gun. Well the MP38 really, while it retains that same look it, really was much more of a first generation
expensive milled submachine gun
If you look at the quality of the machining on this receiver tube
it's really just a coincidence that this is too tubular in shape instead of being some other milled shape
because they put as much work into this as they would have into something like a Thompson submachine gun receiver
This is an interesting element that the Germans added because they recognized that these guns were going to be used largely by
mechanized troops and that was some of the, the original design intent for these submachine guns
were mechanized troops and paratroops who needed a compact weapon. The idea with this is this was originally aluminium,
they also did some stamped steel and some bakelite and as repairs actually wooden guards here.
This is a hook that allows you to put this over the edge of the door or the
the armor side of your armored personnel carrier, your half track, your Kübelwagen
And you can hook the gun over that when you're shooting to make sure that the gun doesn't
unintentionally recoil back into the vehicle and shoot things that you don't want to be shooting
So that's an interesting element that not a lot of other people actually copied.
So a couple of other early elements
this is for both early 38s and 40s - the muzzle, nut had this full threading on it, knurling on it
That's a just a muzzle protector
And then it also has this hook on here, this
machined thing and that's for a muzzle cap. Now they fairly quickly realized that
the muzzle cap was extraneous and unnecessary, so they stopped producing them
and also stopped machining the front of the front sight tower to include them
As I mentioned a moment ago, the magazine wells on the MP38s are smooth sided with a weight-reduction hole, and they have this
There a number of they're a bunch of changes to these guns that are kind of aesthetic only like the pattern of the checkering
On the magazine release button there and so we'll ignore those for the time being
Speaking of the smooth-sided magazine well, the early MP38 magazines were also smooth sided like this
Now they continued that into production of the MP40 before they eventually went to a thinner metal and a rib instead for strength
Another interesting uneconomical feature on the MP38s
This grip frame assembly here. This is bakelite plastic, but the grip frame was actually made out of aluminium
That did not last long into the war effort because of course aluminium was a much more expensive material than steel
and the available aluminium was all going into aircraft production
There was no real need to make a part like this on a submachine gun out of aluminium
So one of the changes with the MP40 was replacing this with steel
Before we move on we'll just take a quick look at the markings here, does say MP38.
27 is the German Factory code for Erma, the MP38s were manufactured only by two companies - Erma and Haenel
And this is a 1938 production gun
And lastly note that the rear sight is actually screwed in place
You've got two, two site settings there
but uh,
the relevant point is that they are
sight base is screwed down
Now moving on to the MP40, we now have
significant simplification, we have a lot of stamped parts. The receiver is now stamped, a couple of large ribs in it to reinforce it
Our front magazine well here is
stamped instead of being machined
It's still flat sided they got away with, got away from the hole in the centre, it was just not substantial enough to deal with
On this particular example we even have a stamped front guard here
this is not original, a gun of this period should have had
a machined steel one. This was added later at some point, the original was probably damaged
And this pistol grip assembly is now steel
And that actually goes all the way up in here and mounts the folding stock
So this is a 1940 production gun you can see it's now marked MP40
And some of these early elements remained on the early Mp40s. Things like the muzzle cover
adapter there, and this style of muzzle nut.
Now moving to a later MP40
we can see a few more changes happening and these get to be pretty small changes, for one thing
we now have a ribbed magazine, and the most visible change here,
and this is the case on most of the MP40s that you'll find, is the magazine well.
That magazine well now has these distinctive stamped ribs to strengthen it
Now it's still a stamped part as opposed to being milled on the MP38
We now have a bakelite protector here
The muzzle nut attachment is gone, and we now have this split knurling on the muzzle nut
Not sure exactly why they did that, they probably decided it was a little bit easier to get a grip on
Now since I know some people are going to ask
We'll take a quick look at disassembling this gun because it's super easy, but it's not necessarily the most intuitive thing
So if you look at the bottom of the grip
Rather the bottom of the stock assembly, you'll find this which looks like a screw, get the stock out of the way
This is not a screw. This is simply a plunger what we need to do is lift it up and rotate it 90 degrees
There you go, you can see that's now sitting up
Now
in order to remove the entire top half of the gun from the lower housing, I'm going to pull the trigger
the bolt's forward, so it's safe and we're going to rotate the whole receiver
clockwise
do that about 90 degrees and
then the two halves just come apart.
Trigger is really simple in this, there is by the way no semi-auto setting on an MP40, it is safe or full auto.
Once we have the lower housing off we can then pull out
the recoil spring
and the bolt
Unlike a lot of open bolt submachine guns this does not have a fixed firing pin
The firing pin is actually connected to the recoil spring assembly,
but the rest of this bolt is very similar to that of an MP18
Now, you'll notice this bolt handle looks a little different than the others.
We'll take a look at that once we're done with disassembly.
The recoil spring is one of the kind of iconic features of the MP38 and 40 in that it's
this telescoping design, the spring is inside here, firing pin's fixed on the front and it all collapses together
Now what this, the advantage of this is that you don't get dirt and grime
inside the spring itself, you might get gunk inside the receiver
but it's a lot easier to clean this off
than to take a coil spring and try and wipe say, sand out of a coil spring, so that's a cool feature
As an open bolt submachine gun these are really simple mechanisms
That's really all there is to it.
Now the design of the bolt handle
was a change that a lot of people think is associated with the change from the MP38 to the 40,
but it's actually not. The 38s and the early MP40s have this standard kind of hook shaped charging handle
That's how it works, and if you want to safe the gun we have a safety notch back here, pull the bolt back,
rotate the handle up into that notch,
bolt's locked in place can't go anywhere
However
this did leave a safety issue
If you happen to be, let's say you're climbing out of the turret of a tank with your MP40 and this hook
catches on the inside of the turret and it pulls back, pulls back, pulls back to say here
At this point it has cleared the magazine,
but it has not caught the sear, if it pulls back to here and then you yank it free -
It will then run forward, strip a magazine out of the, or strip a cartridge out of the magazine and fire
unintentionally and likely shoot you,
this is a problem. Now this rear safety catch doesn't really do anything to ameliorate that
Instead, and this was causing serious safety issues,
this was a problem that the German army was well aware of and their interim solution was actually to issue a leather strap
that you could lock around the bolt handle, kind of like the hammer tie-down on a single action revolver holster,
that would hold the bolt forward and prevent it from going back, but that's really a kludge of a solution
So instead what they came up with in July of 1942 was this redesign of the bolt handle.
With this new handle design
you can push the bolt handle in towards the center of the gun and that locks the bolt in place, when you're ready to fire
you pull the bolt back out, and then it can cycle. That was a much better solution
However,
by the time they came up with it, it was summer of '42 and they had a lot of these guns out in the field
So there was an order put out to retrofit all of the hook safeties with these
Which isn't just a matter of replacing the bolt handle,
they also have to cut a little notch in the receiver here for it to function again.
You can see that, that notch right there and
Apparently, it didn't really work. They were supposed to have completed the transition universally by May of '43
but later in '43 another order came out still talking about getting this update done, and as you can see we have guns like
this
MP40 which is quite early, which never got the update done.
But, that's why that bolt handle is there, that's what it's supposed to do, and this is also a
important safety lesson for anyone who has an open bolt submachine gun
that they are taking out loading up and shooting, is be aware that
safety procedures are a bit different for open bolt guns than they are for closed bolt guns.
In all of its forms the MP38 and MP40
was a remarkably good submachine gun, really the magazine was a bit of a weak point to it
and I personally am not a big fan of the under folding stock, but these guns serve very well
they were well liked by the guys who had them and they did good service, so
hard to complain about that. I would like to thank the Institute of Military Technology for letting me
take a look at these three, there are not a whole lot of MP38s around so it's pretty cool to find
not just one of those but one with the other later variants as well so that we can compare them.
If you're interested in small arms design research, the IMT collection isn't generally open to the public
but it is available by appointment
so check them out, get in contact and arrange a trip down here to do some research or just have a tour of the collection,
I'm sure you'll enjoy it. And if you enjoy seeing videos like this, please do consider heading over to my Patreon page and subscribing there.
It is contributions from folks who do that
who make it possible for me to continue to travel about, find these guns and bring them to you. Thanks for watching!