Hi guys, thanks for tuning into another video on Forgotten Weapons.
We have something pretty fricking amazing today.
This is a Krummlauf. This is a Sturmgewehr with a curved barrel attachment on it.
These get a lot of press, but you don't see very many of them out there.
Of course, as you can see we're at Rock Island Auction Company,
and this Krummlauf device is going up for sale in the September Premier auction.
It does come with a Sturmgewehr, although it is, I should say, not this particular one.
The gun that this comes with is not in the building right now,
so we've mounted this up on a different rifle so that we could show it to you.
Research originally began on this device in about 1943.
What's interesting is it actually started as the use of a large diameter barrel, like a 20mm barrel,
in combination with 8mm Mauser ammunition as kind of a trough.
You curve the large barrel and use it to redirect bullets, but not specifically try to aim them.
And ... there was a bunch of research that went on in this vein, and over time they eventually realised
that actually a tight rifled barrel worked better for curving bullets than a large diameter trough did.
So they eventually came to the conclusion of using a device like this.
This is a 30 degree bent barrel. It's in 8mm Kurz.
And this was actually intended for urban combat, believe it or not,
to shoot around obstacles, out of trenches, that sort of thing.
This is locked in this configuration, you can't rotate it.
So ... the curved barrel is always pointing down.
If you want to shoot left or right you have to cant the whole gun,
and that's fixed by the fact that the front sight post is locked into the casting of this barrel device.
Now there was also a 90 degree version that was made, and that was actually designed for use in armoured vehicles.
So you would have a Sturmgewehr mounted vertically inside a tank or a tank destroyer,
while the barrel would be pointed horizontally. And this could be used to defend against infantry attacking the tank.
Those had a different periscope system. On those the periscope was actually mounted into the hull of the tank,
and of course, it was a 90 degree periscope instead of a 30 degree.
So, ... these got a lot of attention right at the end of World War Two.
Aberdeen Proving Ground did a bunch of testing on them, and came to some interesting conclusions.
We'll take a closer look here,
and discuss what they found and how they worked.
Here is the Krummlauf.
It locks into place ...
using this clamping mechanism.
What we're gonna do to take it off is we unscrew this, and that is going to ...
loosen up the clamp ...
to the point that ...
we can open up these two.
And then you can see that the ... front sight tower, locks in ... just like that.
So that's what locks it in a vertical orientation.
Now to take a closer look at some of the features of this guy. If you see right here, there are two lines,
one on each side of the barrel, of five relief holes.
Those are to relieve gas pressure as the bullet enters the curved portion of the barrel.
That helps reduce wear on the whole mechanism, it reduces the velocity as well,
but of course this is not a long-range weapon, and the reduction in velocity isn't that big a deal.
This triangular sheet metal attachment here was added because it was noticed
that the gas escaping from these vent holes was going straight into the optical system.
So they added this to deflect the gas away.
Now the optic itself ...
(See if we can get a good view here for you, there you go.)
There is a new iron sight mounted inside the optic, a rear sight, that lines up
with ... (there you go) with the regular front post.
There's a 30 degree mirror in there, and it's actually not that terrible of a sight, it works reasonably well.
You can see the screws holding this together were safety wired.
That's a standard German thing on this device to make sure that they didn't vibrate loose
Here from the front you can see
the replacement rear sight lines up,
... with the hooded front sight here.
Now, when they put this together there is a 4 inch section here,
the actual curved section is 5.5 inches of barrel,
and then there's a 4.5 inch straight section at the end.
This is all rifled. The very beginning, about the first centimeter of ...
the curved barrel attachment right back here,
is actually bored out to 9 or 10mm, and what that does is allow the bullet to re-centre itself.
Because the bullet does actually jump from the rifled Sturmgewehr barrel here
into a separately rifled curved barrel.
And the Germans did some experimenting, they determined that there was really no advantage to
taking the effort to line up the rifling to make sure that it matched.
It just didn't matter, frankly.
The accuracy was no different when they just jumped from one rifling pattern to a different one.
One thing Aberdeen Proving Grounds determined, or found, during their testing after the war
is that this curving action did actually tend to break bullets at the cannelure.
And so you'll see stories about how this, like, fragmented bullets and had a sort of shotgun effect.
And it actually sort of did. Aberdeen has a photo of some projectiles that they test-fired into hay,
you know, to ensure that they wouldn't damage the bullets before recovery, and most of them are broken and fragmented.
Unfortunately, we can't shoot this one, of course, because it's on consignment for the auction.
And the chances are most people will never be able to fire one of these,
because the barrel life is only a couple hundred rounds before the forces from
the curved bullets, really basically, just destroy the curved barrel device.
... For firing, unfortunately we're pretty much gonna have to stick with what the US proving grounds
experimented with and determined after the war.
So I have to say in terms of practicality this is kind of dubious.
Mounting this Krummlauf on the end of the barrel makes it extremely heavy and bulky,
and I don't think I've ever handled a worse balanced rifle than this.
They never saw all that much use. They didn't go into mass production, although they were slated to.
But you know the sight picture actually works, the mirror works.
If you got to shoot around corners, it might not be a bad idea to have one guy in a squad lugging this thing around.
So, if you want this, as I mentioned, this will be up for sale at the Rock Island auction.
I don't know what its gonna bring, but there are very few of these in private hands, so best of luck to you.
Thanks for watching. Tune in again to ForgottenWeapons.com.