Hi guys, thanks for tuning in to another video on ForgottenWeapons.com.
I'm Ian McCollum, and today we're going to talk about a cartridge from Spain in the early 1950s.
A cartridge that is pretty obscure but technically very interesting.
And one that's also responsible for a pretty pervasive myth
about CETME rifles, and in particular FR-8 and FR-7 bolt-action rifles.
So the cartridge is the 7.92x41mm CETME cartridge.
And where this begins is actually Spain in February of 1950.
The Spanish government wanted a new rifle, a semi-auto rifle.
Of course at this point they're still using Mauser bolt-action rifles.
And they have a pretty extensive set of experimental designs going on,
and what they decided to try and take advantage of was this group of Mauser engineers
who had been responsible for working on a lot of the German small arms developments
involved in the StG 44 and 45 in World War Two.
A lot of these guys were at that point working in France
for the French, and they weren't very happy with it.
And the Spanish thought that they could basically just poach this group of engineers,
and have these guys design them a cool new rifle.
So in 1950 the Spanish military, talking with one of these German engineers,
came up with an RFP, basically a list of the things it wanted in its new rifle.
And these were a maximum weight of 3 kilograms, that's 6.6 pounds, that's not very much.
An effective range of 800 to 1,000 metres, that is quite a lot.
They wanted it to have a folding stock
so it could be used by airborne troops, and vehicle crews, and such.
And they also wanted it to be ... capable of fitting both a bayonet lug and a grenade launcher,
not necessarily at the same time.
And the Germans, these Mauser engineers, got together and started talking amongst themselves, and
realised immediately the conundrum, the problem that this set of requested characteristics posed.
Namely, they wanted a rifle that was effective at very long range, and also extremely light.
And by the way, this was a select-fire rifle, had to be full-auto.
And these are basically impossible things to balance.
... In order to have a rifle that is effective at 1,000 metres,
it has to have a lot of muzzle energy to get a bullet there.
And remember it has to get a bullet there like above the transonic range,
because when a bullet starts to go through the sound barrier
it's going to impact its own sonic boom, its own pressure wave.
And that's going to destabilise the bullet substantially.
So your accuracy really drops significantly when you cross the speed of sound.
So they had to keep it supersonic out to 1,000 metres,
and yet they also had to have it light enough recoiling
that you could actually fire the thing in full-auto with some usable result.
When these same engineers had worked on this problem during World War Two,
the solution was make a much smaller cartridge, make the 8x33 Kurz cartridge.
Where you don't care that it's not effective at 1,000 metres,
because no one's going to be using it out there anyway.
That's what combat documentation showed:
past 500 no one was ever actually taking effective shots anyway.
So why bother making a cartridge powerful enough to do it?
But the Spanish maybe didn't have the same combat experience,
they insisted on the long effective range.
So, what the German engineers came up with was
they said they had to increase the weight to 4 kilos from 3.
So maximum weight goes from 6.6 pounds up to 8.8 pounds.
And at that point they thought this was a feasible project.
Now I should point out, the calibre that was chosen for this rifle was 7.92mm (say 8mm).
Really only because that was the calibre that a lot of these guys had experience with,
and since there was no existing international standard, they just decided to stick with that.
This does pre-date the 7.62 NATO development trials.
We'll touch on those, those have an impact later on in this story.
But, suffice to say they stuck with 8mm.
And one of these German engineers was a guy by the name of ...
Dr. Engineer (so a Doctor of Engineering) Günther Voss.
And he came up with a really brilliant solution
to what appeared to be an insoluble paradox.
And that was a bullet that was extremely long.
The actual projectile itself was 1.8 inches long, that's 46mm.
I mean this is massively longer than anything anyone else had ever done.
And it had to be that long in order to have a really good aerodynamic
... well, what we would call a ballistic coefficient today.
It had to be a really good aerodynamic shape, nice and long,
so that it ... doesn't lose a lot of velocity as it travels.
That's essential, keeping it moving fast to maintain accuracy at very long range.
However, in order to minimise the recoil
they made it out of aluminium, so it's a very lightweight bullet.
This thing came out at basically 106 grains, that's 6.8 grams, a really lightweight bullet.
Now, that seems like a good solution right there,
and if ... it was as easy as that people would have figured this out long ago.
The problem was you can't quite get away with that,
because if you have that light of a bullet it doesn't stabilise well.
And so what Voss figured out, ... really the genius element of this bullet,
was around the middle of the bullet he had a ... semi copper jacket.
So the bullet is kind of lozenge-shaped,
so only the middle section is actually in contact with the barrel.
And on that point he had wrapped copper around the outside of the bullet.
It was still an aluminium core, but it had
... basically a copper band around about the middle half of the bullet.
What this did - first of all it made for better rifling engagement,
better than trying to run aluminium on ... steel, copper bullets are better for that.
But more importantly, it added this much denser material around the outside of the bullet.
So that when the bullet is spinning you had a lot of mass on the outside.
... Think of this like a flywheel, it kept the bullet spinning and stabilised
much better than an aluminium only bullet would have.
If ... the bullet was solid aluminium it wouldn't have much inertia keeping it spinning.
The copper did that.
And so this combination of an aluminium body with a copper band around the middle
actually gave them a bullet that was low recoil,
and maintained velocity out to 1,000 metres, or a little bit more.
... The number they actually came up with,
the goal they were looking for to assure controllable full-auto fire
was 0.75 kilograms per second of recoil impulse.
And to put that in perspective, 7.62 NATO has, in its original form,
has a recoil impulse of like 1.16 kilograms per second.
So we're talking maybe something like 60% of the recoil impulse of 7.62 NATO.
And that was to allow it to be fired full-auto effectively.
This combination actually worked.
And these ... former Mauser engineers later to become HK engineers,
at this point in the story working for CETME in Spain, put together a rifle.
They actually had two: they initially experimented with both a
flapper-locked rifle action similar to the G43,
and a roller-delayed action that was the evolution of the Sturmgewehr 45(M).
... This whole thing becomes very quickly the HK91 or HK G3 rifle.
At this point they put it together, they do some testing.
They have what they called a Modelo 1 and a Modelo 2,
1 is the G43 action, 2 is the roller-delayed action.
The Modelo 2 turns out to be better.
It's a lighter weight gun, it allows them to have more strength in the parts where they need strength,
without having to add mass for things like gas pistons.
And that rifle looks really good.
By 1952 it was in trials in Spain, in fact they had the prototypes ready by like September of 1950.
So a fairly rapid development process,
largely because this rifle was the direct development of the Sturmgewehr 44 and 45.
So the engineers building it already knew the basic principles of what they were doing.
They were just adapting it to some specific Spanish requirements, this new cartridge,
and improving it in ways that they had been
wanting to improve it since World War Two.
So the rifle goes into Spanish testing in 1950, through ... the end of like 1952.
The Spanish really like it, this looks pretty good.
Aberdeen Proving Grounds in the US gets one in 1954,
and runs through a whole battery of tests where it does really well.
This is a very reliable rifle, it's a pretty accurate rifle.
It is a remarkably effective rifle to fire full-auto. Seems pretty good.
Now, you can recognise these early CETMEs because they have a curved magazine,
unlike the straight magazine that would follow later. So they're pretty easy to spot.
And they look really crude and kind of awkward, very minimalist.
And that's because, in order to make the strict weight limit on this rifle,
they're keeping all the extraneous stuff off.
So, for example, the handguard is the bipod.
When you fold out the bipod, you no longer have a front handguard.
And that's a weight saving measure.
That bipod is pretty much necessary to have any chance of hitting anything out at 1,000 metres, but.
Where this all goes awry is when
... the 7.62 NATO development process becomes known to the Spanish.
They decide that they do in fact want to use this
new European international standard cartridge.
And the problem is you can't just drop that into this CETME Modelo 2 rifle,
because the CETME has been designed for a remarkably low-recoil cartridge.
And when they almost double the recoil impulse of the cartridge,
by say, dropping 7.62 NATO into it,
you have serious durability issues with the gun.
You start cracking receivers, and the gun's beating itself to pieces.
So the CETME team went through a couple of iterations
hoping that they could preserve this really fairly innovative bullet design, and none of it works.
Ultimately what they have to do is adapt a cartridge
that is dimensionally identical to 7.62 NATO.
And what they do is they reduce the bullet weight from 147 grains to 113 grains.
It's ... just about the same weight as their original very long, ballistically elegant bullet.
They ... make a hybrid lead/plastic core with a copper jacket.
So it's the same size as a standard 7.62 NATO bullet, but it weighs a little bit less.
That becomes known as the 7.62 CETME cartridge.
And with that cartridge the rifle ... works fine.
The problem is this didn't really last effectively, Spain wanted to use the 7.62 NATO.
And ultimately what they did is beef up the CETME rifle to the CETME Model C,
which is the one that was ultimately formally adopted in large numbers by the Spanish military.
And that's the CETME that we're familiar with today.
That's also the rifle that would be basically
adopted by the German military as the G3, the Gewehr 3.
So by that point the 7.62 CETME is gone. This was only a very short term,
"Maybe we can get away with having our own special cartridge,
and still maintain some of the lighter recoil benefits of the rifle we originally had."
And it went out the window.
Unfortunately, today there's not a lot of information about this cartridge,
and the theory has developed along the way (well before the internet I believe),
that 7.62 CETME was the cartridge for the CETME rifles
because it was lower powered, and the CETME rifles were
- take your pick of which story -
made of cheap Spanish steel, or badly designed, or something, you name it,
and couldn't handle 7.62 NATO so they had this lesser cartridge.
And this story has kind of wiled its way onto the Spanish bolt-action rifles from the same period.
The FR-7s, which were early pattern, like I think, 1893 Mausers ... re-barrelled for 7.62.
And the FR-8 rifles, which were more modern [1943] pattern rifles, ... re-barrelled to 7.62 NATO.
These were both used as basically National Guard, training rifles,
second line rifles, by the Spanish military.
People assume that the FR-7 in particular, because it's the older version of the Mauser,
can't handle the pressure of 7.62 NATO, so it's supposed to fire 7.62 CETME.
This is in fact not the case, the FR-7 and FR-8 were both
intended to be fired with standard 7.62 NATO ammunition.
That 7.62 CETME light loading just did not last very long,
and was never made a formal adopted cartridge.
So, that is the story of what started off as a cool German post-World War Two innovation
that ended up kind of clobbered by 7.62 NATO.
It is in fact one of many potentially interesting ideas
that met their doom at the hands of American insistence
on a cartridge that had all of the power of the original .30-06 Springfield.
Anyway, hopefully you guys enjoyed the video. Hopefully you learned something interesting today.
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Either way, thank you very much for watching.