Hi guys, thanks for tuning in to another video on ForgottenWeapons.com.
I'm Ian McCollum, and I am here today
at HK's Grey Room in Ashburn, Virginia,
taking a look at some of HK's submachine guns.
Now of course, the submachine gun that HK is
really known for is, naturally, the MP5.
However, for some time HK has been trying to come up with a modernised,
more economical alternative to the MP5.
They made some prototypes that didn't really go anywhere, which we'll cover in a separate video.
And ultimately what they put out on the market in about 1999 was the UMP,
the Universal Machine Pistol, or universal submachine gun.
And this is a significant departure from the MP5 mechanically.
Instead of being roller-delayed blowback, this is just a simple ... blowback submachine gun.
It does fire from a closed bolt, which is a nice carry over.
One of the advantages, one of the really nice elements of the MP5 was
its closed bolt, hammer fired operation.
Which meant if you want to take one precise shot,
and especially in a law enforcement context that's often how a submachine gun is used.
It's primarily a 9mm semi-automatic carbine,
with the option to flip the switch and have full-auto if you really need it.
And in that context, having a closed-bolt firing gun is definitely an advantage.
It makes for, in a practical matter, a much more accurate first or single shot.
You don't have the bolt slamming forward when you fire that shot.
So the UMP does maintain that closed-bolt hammer-fired functionality, which is nice.
It retains a lot of the handling elements of the MP5.
But instead of having a stamped sheet-metal receiver
with a bunch of relatively complex milled parts,
this is an extremely simple gun with a polymer receiver and a very blocky square bolt
that's really much easier and faster and cheaper to produce.
So, let's pull this apart and take a closer look at the internals.
There's not a whole lot in the way of receiver markings, just HK UMP.
On the other side we have a warning to read your owner's manual.
And then the bolt is marked HK and the calibre.
These are made in three different calibres: .45 ACP, .40 Smith & Wesson and 9mm Parabellum.
So to make sure that you don't mix up the bolts, they are marked.
The fire control group carries over all the same basic handling from the MP5.
There are a number of different fire control groups available from HK on this.
This is safe, semi-auto, full-auto.
You can also get versions that have 2 round bursts in there,
either with or without the full-auto.
So a bunch of different combinations that can be made there.
The magazine release is just an ambidextrous paddle on the bottom.
Again, carries over from the MP5.
As does the charging handle, located here on the top left.
That cycles the bolt, and you can lock it open
by lifting the charging handle up. Again just like the MP5.
The sights do not carry over.
Instead of the classic HK diopter sight, this has a two position flip peep.
You can either have a V notch, or an aperture.
The front sight is just a hooded trapezoidal post.
Of course most users are probably going to mount an optic.
The UMP comes with a piece of Picatinny rail on the top of the receiver there,
so you can mount an optic of your choice.
And the folding stock is also standard.
Just push the button, fold it in, and it's going to lock onto this little tab over the ejection port.
A lot of the elements of this gun come from the G36 rifle.
We'll go ahead and pull it apart, this is very standard HK.
Pull a push pin here, pop that all the way out.
And then, like the G36, you don't actually remove the stock,
it's fixed to the ... upper receiver assembly.
Instead, you fold the stock,
and then we can pull the fire control group off, like so.
And then we can just pop this out the back.
So it is this back plate on the fire control assembly
that holds the mainspring and the bolt in place.
So the spring comes out, captive of course.
And ... the bolt!
Now the weight of the UMP isn't all that different from the MP5.
And it's largely because of this bolt.
The UMP loses a lot of weight
by having a completely polymer frame and stock and grip assembly,
but it gains a lot of that weight back with this bolt.
Where the MP5, being a roller-delayed blowback,
is able to reduce the mass of the bolt quite a lot.
Which it then picks back up by having a metal frame and receiver, so.
This is a hammer fired gun, so there is a floating firing pin.
Or rather there would be a floating firing pin,
this particular gun on display has had its firing pin removed.
But the firing pin comes back here, this pin prevents it from falling out.
And it just gets hit by a hammer at the back of the bolt assembly.
So this top bit is what the charging handle pushes on,
and it's there just to give it mass to delay opening sufficient to be safe.
I don't know if you can hear that at all, but
you'll notice that there is this welded plug at the back of the bolt.
The inside of the bolt does actually have a metal powder in it
which acts as an anti-bounce mechanism. So that absorbs some of the inertia.
When the bolt slams forward, instead of bouncing open,
that powder absorbs the energy, moves forward and keeps the bolt closed.
That's an important aspect for ... a blowback machine gun.
The fire control group, as well as the entire lower assembly, are basically all polymer.
There's a little metal insert in the face of the hammer,
but other than that, this is all polymer, and this is very heavily inspired by the G36.
In fact I'd bet some of the parts in here are interchangeable with the G36,
although don't quote me on that.
If they're not interchangeable, they're certainly the same basic design.
And there's the upper receiver with all of its parts out.
The other distinguishing feature between the UMP and the MP5 is rate of fire.
The UMP was deliberately made to be a relatively slow firing gun.
In .45 Auto with 230 grain ball ammo, this will run at about 580 rounds per minute.
Which obviously sounds like a lot, but that's relatively slow for a submachine gun.
It's not quite as slow as the M3 Grease Gun, which was more like 450 to maybe 500.
But it is definitely slower than the MP5,
which is on the order of 750 or maybe 800 rounds a minute.
So, you can speed up the rate of fire by using lighter weight ammunition, like 185 grain .45,
or in 9mm they're a little bit faster, more like 650.
But this still gives you an option, if you want an HK submachine gun,
for something that has a little bit lower rate of fire.
On a similar note, the magazines here are 25 rounds for the .40 and the .45,
and 30 rounds for the 9mm.
Now the UMP was largely targeted at the United States law enforcement market.
Which we can see in the calibre choices.
Unlike a lot of other submachine guns out there, this is available in .40 Smith & Wesson and .45 ACP.
Now the .40 Smith & Wesson isn't all that popular today,
but in 1999 it absolutely was, that was the law enforcement cartridge du jour.
Which we can see today in all of the surplus
.40 Smith & Wesson pistols being sold by police departments.
At any rate, what HK did was design a submachine gun where
the receiver ... where the standard mag well is large enough for a .45 calibre magazine.
And then they also made .40 and 9mm mags to fit it.
So the .40 Smith & Wesson and the .45 ACP cartridges
are not particularly popular outside the United States.
But that did give the UMP sort of a reason to exist,
and a reason to be purchased here in the US.
There aren't a whole lot of other .45 calibre modern submachine gun options out there.
I know there are some, I know people are at this very moment
furiously writing them in the comments below,
but that was one of the things HK was trying to use as a specific rationale to support the UMP.
So in fact you can notice here, that's our .45 calibre mag, that's a 9mm magazine.
That's 25 rounds, this is 30, and it fits right into the same magazine well.
So you can actually swap these guns over by changing the barrel, the bolt, and the magazines.
The same frame works in all three calibres, which
really goes to show that that was a deliberate intention of the gun from the very beginning.
Anyway, I'm wandering off a bit here.
These have proven to be somewhat popular.
They've made some sales in the United States, mostly in .40 and .45.
Sales overseas in Europe involve a lot more 9mm, it's a more popular cartridge over there.
And ... the various law enforcement pricing schemes
between the UMP and the MP5 probably have something to do with that as well.
But ... it really is a testament to the MP5
that it's a really hard gun to dislodge from the market, even by HK themselves.
It is in fact the only roller-locked gun that HK still manufactures today
because it continues to be a very popular weapon.
Anyway, that has been your introduction to the HK UMP.
Hopefully you enjoyed the video. I'd like to thank HK for giving me access to their Grey Room
to bring guns like this to you guys.
Thanks for watching.