Articles, Blog

Steyr ACR: A Polymer Flechette-Firing Bullpup From the 90s


Hi guys, thanks for tuning in to another video on ForgottenWeapons.com. I’m Ian McCollum, and today we’re going to take a look at a super cool rifle. This is a Steyr ACR, that stands for Advanced Combat Rifle. Because this was a part of, well, this was Styer’s entry into the US military program which was tasked with improving on the M16A2 rifle. Now that program started almost as soon as the army adopted the M16A2, and what they wanted to do was improve hit probability. So the problem was, when you have
soldiers who are stressed, and, you know, both physical and emotional stress on a
battlefield, and they’re getting shot at, and they don’t know where it’s
coming from, and they’re jerking the trigger, and they’re firing in full-auto, and
recoil is bouncing the guns around, soldiers in combat don’t tend to hit very much.
Unless they’re really well-trained, and really experienced veterans. So, the idea was maybe they could come
up with some piece of military hardware that would compensate for this, and allow
soldiers to get better hits, or get more hits, without having to be super well-trained or experienced.
That was the Advanced Combat Rifle program. And, generally speaking, what they were trying
to do with this was fire multiple projectiles with every pull of the trigger. The idea was
to have something, kind of like a shotgun, but at an effective rifle range. So, of course,
the advantage of a shotgun with, say, buckshot is you pull the trigger once and
you get 9 or 10 to 12 pellets going out there in a spread, and how big of a spread depends
on how far away the target is, you know, it gets bigger as it travels downrange. But you
don’t have to necessarily be exactly on target. If you’re slightly off to one side,
some of the pellets will hit your target, even if most of them don’t.
And that’s what the Army was going for. In fact, the Army had been investigating this
sort of idea for decades, back into the 1960s with the Special Purpose Infantry Weapon program. And this was simply the most recent, well, when this was
made, this was just another iteration of this program. And so there were two ways that they looked
at doing this sort of improved hit probability. One was by firing multiple projectiles simultaneously.
Colt’s entry into the ACR competition fired a duplex cartridge, which
means it was basically a 5.56 cartridge, but instead of having one bullet, it actually had
two bullets nested on top of each other. So every time you pulled the trigger
you got one recoil impulse, but two bullets went down range which,
in theory, meant you had a substantially better chance of at least one of those
bullets hitting what you’re trying to shoot. Some of the … well, for example, the HK
entry into the program was the G11 rifle, that fired a three round burst at about 1,800
rounds per minute. The idea there was you pull the trigger once, you’re going
to get three separate recoil impulses but they’re so close together that the
rifle doesn’t have a chance to substantially climb off target before the third one has left the
barrel, and thus you have a better chance with three projectiles of hitting your target. The Russian AN-94
did the same sort of thing with a two-round burst. Well, … the Steyr ACR here did a couple things,
it had a three round burst mechanism, although it only fired at about 1,200 rounds per
minute. But it also, instead of firing traditional bullets, it fired flechette cartridges, meaning basically a long
needle-like cartridge [projectile] with some fins on it. And the three round burst on this fired at,
well I said, 1,200 rounds per minute. The individual cartridges, the flechette,
was about 10 grains, that’s about 0.66 grams. So an extremely lightweight projectile, travelling
really fast. The muzzle velocity on this thing was 4,800 feet per second. That’s about 1,450
metres per second. That’s like 50% faster than any standard, even, you know,
a high-velocity 5.56 rifle bullet. And the advantage to that was, well,
first off, with a very light bullet going fast you have less felt recoil and you have a much greater point-blank range.
Meaning the bullet, because it’s going so fast, doesn’t drop very much, or the flechette.
So out to at least 300 yards you could just hold your sight dead on target and
you’d make a hit. You didn’t have to try and compensate for elevation, and that helps.
That sort of estimating your holdover with unknown ranges is a difficult thing to do, and
takes a lot of practice and training or experience. As I’m sure you’ve already noticed, the Steyr ACR
is a bullpup style of rifle, magazine at the back, in fact, very close to the very back of the rifle.
We’ll take a look inside this in just a moment. Controls are really quite simple. The magazine release is back here,
push that in and the magazine comes out. This is a, interestingly, a double stack,
single feed magazine. And when you see inside the rifle, you’ll see why it does
have to be a single feed magazine. Interestingly, and first off, … you’ll notice the
similarity between this and, say, the other magazine that Steyr was kind of
specialising in at the time, the Steyr AUG. Quasi-transparent,
very similar style of magazine. We have some numbers moulded on the
outside here, so you can see from the outside how many rounds are loaded.
And this is only a 24 round magazine. That seems to me to be a little bit odd,
given that its purpose was firing a lot, firing three round bursts. I kind of would
have expected a larger magazine, but that’s what they had.
So that’s what we’ve got. You’ll notice there is no bolt release lever anywhere,
because this is actually an open bolt firing weapon. Again, we’ll touch on that in just a moment. The safety is a push-through button
right here. So a single dot is fire, semi-auto. Pushing it all the way through to two dots gives you
full-auto, which is actually a three round limited burst. And then you can push it all the way through on the
other side to expose the white dot and that is safe. We have a sling swivel up here, which appears
to be able to be reversible if you’re left-handed. The other sling swivel is on
the top of the back of the stock. … Of course, there’s a rail on top of
the gun. There is a front sight up here. I believe the rear sight is a unit you would
have to put in to replace this optical sight. That is a low powered optic,
I don’t know the exact specifications. It looks to me like it’s about 2 power,
maybe 2.5 power, not much more than that. A neat little muzzle brake design,
flash hider and brake. You’ll notice there are these circular holes to vent gases
upward upon firing to help control muzzle climb, as well as a birdcage style of flash hider. And then the last control on there is this very
AR-like charging handle. So pull that back and it locks the bolt open, you then push it forward.
Like I said, this is an open bolt firing rifle, so there is no need for a bolt release,
because the bolt release is … the trigger. While, unfortunately, I’m not able to fire
this for you guys today, I do have a round of the ammunition to show you. So it is
roughly the same size as a 5.56 cartridge. (Green tip here for comparison’s sake.) If
we look at this up close, because it has a semi-translucent case, you can see right
through it. That’s our main powder charge. Right up here is the sabot, so this grips
around the front of the flechette projectile. This actually does engage with rifling in
the barrel. It has a very slow rifling twist, one in 85 inches, which is
like one in 213mm [2160mm?], but it does give the sabot a spin, stabilisation,
in addition to the fins that it has. We have this little port in the front, that’s where
the projectile is going to pop out of the case. And there’s nothing on the back.
This actually has a ring primer, so this silver band at the back is a primer. You
can actually almost think of that as a rimfire primer, because it does go all the way around the
case. So there is a single firing pin at the top of the chamber, but because the
primer ring goes all the way around, … it doesn’t matter what orientation
the cartridge is in, in the magazine. Speaking of which, there is the
cartridge loaded in the magazine. So, we have a slot in the back, that is where the
cartridge is going to be pushed out forward, directly into the chamber.
So let’s take a look at that. Field stripping is very simple.
You push in this button, and … pull the back of … the stock off. So the way this thing works is
really pretty slick and pretty cool. This is the back end of the barrel. So it’s a
very long barrel, goes all the way to the end. The magazine (by the way when we’re
in this configuration, the magazine sits basically here, right behind the action). There is a chamber in here, a firing
chamber, that actually … slides vertically up and down, and it’s
connected to this pin. So when I pull the cycling handle back, you can see the chamber right there. This action rod is connected to the gas piston
up in the front end of the gun and it’s going to (sorry, kind of takes two hands to open this
thing all the way up, it’s got a stiff piston on it), but this locks open,
because it’s an open bolt gun. … You can now see that the magazine fits basically, right there, and this is our feed system. This little block, right here. When you pull the trigger, this whole
assembly, this frame, goes sliding forward, this little nub, right there, pushes
a cartridge straight into that hole, where it goes into the chamber.
It then lifts vertically up like this, hits the firing pin, and
immediately upon closing, fires. Now you can see how this would be a
slick locking system, because once the once the cartridge is … in line with
the barrel, there’s no force pushing it down. So it’s pretty easy to lock that
sliding chamber in the upward position. Now when it comes to ejection, there is
an ejection port right here on the bottom, and this actually ejects before it fires.
There is no … purpose-built ejector, the cartridge that you are feeding
actually works as the ejector. When one cartridge gets pushed into this chamber,
when it’s in the downward position, it actually pushes the existing
spent case out the front, right in front of it. That’s something that you can do with this neat
little polymer case, because it has no rim on it. So, it can go from here, slide into the chamber, and then get pushed right out the front of the chamber again, after it’s been fired. So, a little ejection port down there. Don’t know
how well this would have fared with malfunctions. I would think that it’s actually a simpler
system, less likely to malfunction, at least as far as the technical
aspects of ejection, because you’re not worried about a spring-loaded
extractor or gripping on the edge of an extractor rim. That said, … I’ve seen a few little excerpts from
people who were involved in test firing these, and they said they weren’t all that reliable,
so I would suspect that would have to do more with feed malfunctions. Problems of
the cartridge jamming going into this chamber, as well as, quite possibly durability issues.
Because this is a plastic cartridge, this would probably be relatively easy to deform,
certainly much easier to deform than a brass case. And if you had a cartridge that was a little bit
squished, it would very easily cause problems. Now as for the actual gas system,
it is, unfortunately, located up here. I think the way you’re supposed to get this out is there’s a
little hex head screw here, connected to the sling swivel. Unfortunately, when I tried to take this one out,
it does not budge, and I put quite a lot of force on it. As much force as I was willing to put
on a prototype machine gun like this. It didn’t move, so I gave up. I’m not willing to
break this gun to try and show you guys the inside. The way it works, however,
is an annular gas piston up here. So, the outside of the barrel actually acts
as the inside surface of a gas piston. This is kind of like the Mauser G41,
or the Walther G41 for that matter. And then there’s a sleeve over the outside of the
barrel, gas is tapped out of the barrel into this sort of concentric piston area, which then pushes
this assembly backwards to cycle the gun. It is a remarkably simple action mechanically,
it is fairly easy to manufacture, and overall a far simpler system
than the G11 that HK came up with. Couple other things I do want
to point out about the rifle. I have not had the chance to shoot it,
but handling is really quite nice. It’s a very short, compact little rifle,
doesn’t weigh very much. The cheek rest, the cheek weld,
going into this optic is quite good. Now the optic itself, … it’s a crosshair
with a large circle in the centre, which is actually very similar, kind of like the magazine
and the trigger guard, similar to the Steyr AUG. I don’t know how good that really is, I suppose for close, fast shooting
it’s probably decent. For long range, maybe you get some effect,
kind of like an aperture sight, where your brain will naturally try and
put the target in the middle of the dot. Without actually trying it, it’s hard for me
to say, I don’t really have any substantial trigger time on an AUG with that
style of optic. So I can’t refer to that. The trigger pull is kind of interesting, in that it’s very, very crisp and very short, for semi-auto. And then when you put the gun into full-auto, it has a much longer, much heavier, trigger pull to it. So, I don’t know if that was
intended to sort of remind the shooter what mode they’re in, or if it was just if
you’re in full-auto you need to be a little more sure that you actually want to dump three
rounds downrange than if you’re in semi-auto. Or maybe it was just an attempt for
semi-auto to allow better accuracy by having a better trigger pull. Either way,
… it’s an interesting thing to notice. … It is limited to a three round burst. I think that’s kind of … about it. There is a … DoD, like a VHS tape, documentary
that was released in 1991 about the ACR program. And that has some shooting
footage from this, as well as all of the other contenders, the HK G11, the Colt ACR and
the AAI, the Advanced Armaments Inc gun. So if you’re interested in hearing more about it,
and what the Army was trying to do, and their excellent projection that by 1996, one of
these guns would be the new standard army weapon, definitely check out that US Army documentary. Ultimately, the Steyr ACR … had some good
points and some bad points. On the good side, it was one of the least … it was in fact
the least expensive rifle in the program. It would have cost less than an
M16, at the time, to manufacture. It was a pretty darn lightweight gun, this
weighs in at just over 7 pounds, about 3.25 kilos. It’s relatively short because of the bullpup configuration. It’s pretty simple, it has a lot going for it in that way. The biggest problem that it had was accuracy. And this could have been … fixed to some extent, but in the iteration where it was actually being
tested by the Army, in late 1980s early 1990s, the case material hadn’t really
been completely figured out yet, and the front of the case would open up and
release the cartridge at varying pressure levels. Which meant you kind of
got varying muzzle velocities. And the upshot was that the accuracy on
this was about half that of a standard M16. And that was, well, that was really kind of a problem.
When the overall goal is to increase hit probability, sacrificing accuracy is, well,
not something you really want to go for. Ultimately, the result of the program was
that none of the rifles that were suggested, none of the rifles that were supplied, were
able to meet the goal. And the goal had been to improve hit probability by 100% over the M16,
so it really was a pretty lofty goal. They weren’t able to make it and so,
like every similar sort of burst fire, flechette firing, shotgun style research program
that had led up to this, this was just cancelled. All the guns went away, and we’re left with just a very small number of the prototype rifles still floating around, mostly in museums. Very lucky to
have gotten my hands on this one. So, hopefully you guys enjoyed the video. Not often we get to take a look
inside something like a prototype ACR. If you do enjoy seeing this sort of thing on the web,
please do consider checking out my Patreon account. It is folks there, folks like you, who
make it possible for me to travel around, find very cool guns like this, and bring them to you guys. Thanks for watching.

100 thoughts on “Steyr ACR: A Polymer Flechette-Firing Bullpup From the 90s

  1. Gah it's so cool, I just want one to run around with and pretend like it actually works, like a kid with a toy space gun.

  2. It was such a massive shame to have them build the gun and actually make it work, only to have it be swept into the dustbin of history.

  3. hey.. can you do some videos on the Metal Storm series of caseless ammunition guns that fire 1 million rounds a minute? please!!

  4. I feel like we will see these flechette rounds again but with a magnetic rail system instead of powder. In theory, you could fit hundreds of rounds in a magazine if not more. The issue of course would be powering it. But I think very likely the future of battle rifles. High velocity, range, capacity, weight, you name it.

  5. shotgun but at rifle range… Do you mean a Pulse rifle? a pulse of 3 or more projectiles with one pull of the trigger?

  6. I wonder how effective the flechettes were compared vs a normal bullet in terms of damage / penetration / etc. My immediate thought was how the AK was so much better than the M16 in Vietnam primarily b/c its bullets would actually go through brush/small trees (and of course not get gunked up and fail in the humidity), and how this has an even much lighter round than a .223 going even faster…

  7. Looks like it would be prone to misfeeds if the stock doesn't sit perfectly right, given that it's the only thing that holds the mag in line with the chamber.

  8. Maybe I'm mistaken, but I would think that unless the plastic is extremely high temperature, after heating that chamber up a bit, the spent cartridge might melt while waiting to be ejected, possibly causing a jam. I wish they had worked this and other issues out. The steel flechette was a NASTY armor piercing round, and because of the fins, it was quite a shredder.

  9. That program was doomed to failure anyway. You don't need to improve the weapon when you can improve the soldier using it.
    Example: Sharpshooters of the revolutionary war 1776.

  10. If the ATF views the Double barreled 1911 as okay, and a shotgun was okay, shouldn't a burst fire rifle or pistol be along those lines more so than a fully automatic machine gun? It's a fixed burst.

  11. if it jams its a pain to clear its going to be a pain to clean and wear on the lifter system may make a short life all in all if cheap per copy maybe I have a friend that was COO at colt back then and colt's submission was better but still not as good as a M4. Unless something really new is developed we are at the pinnacle of combat rifle design.

  12. 25.4mm per inch. If the twist ratio is 1 rotation to 85 inches, then it would be 1 rotation to 2159mm's. I think cm was confused with mm, 2.54cm per inch.

  13. Wait so if acr stands for advanced combat rifle then the Dodge viper acr is the Dodge viper advanced combat rifle?

  14. >Neon Genesis Evangelion released in Netflix
    >rewatch again when the last time i watched i was still a 10+ years old kid in the 90s
    > realizing that Eva's Pallet rifle has a similarity design as Steyr ACR

  15. It's like an engineer built a gun in the basic shape of all other rifles, but without knowing how the inside of all other rifles/ammo look. The design of the ammo and action is exquisite. Amazing.

  16. I love the idea of shooting sabot rounds though if you're shooting fin stabilized rounds you have to do it through a smoothbore a la modern tank gun barrels. The plastic casings are problematic though. Unless they could get the chemistry right I think brass or steel would be preferred. I think a lot of problems with these advanced rifle competitions were that companies were trying to sneak one in on the the military and then work the kinks out later.

  17. I like how blank looking it is, why is it the odder a gun is the more I like it, more so than actual functional ones lol.

  18. this gun is alien tech because you just did not open that screw and show us the rest of the rifle lol

  19. Flechettes are damned ammunition ! v0 speed > 1400m/sec, range: 3000m, steel armour 35mm penetration @600m … and terrible injuries at human bodies !

  20. This gun looks like it was designed by someone who didn't know anything about guns, and was described by someone else how a Bullpup looks like, without having access to any refference photos.

  21. This seems like it would have had the best chance if they ever had the time to get the ammunition figured out. The gun itself seems really well designed while also retaining simplicity that makes it easy for armorers to deal with. The G11 is technically superior, but would be Hell on Earth for logistics.

  22. I am from austria and all the praise of Steyr hbere in the comments fills me with pride 🙂 Thank you for recognizing my home lands engineering efforts!

  23. The ring you can see in the scope covers a 1.8 meter target at 300 meter (sorry but metric system only 😁) . The magnification of the aug scope (or STG77 as it is called in the austrian army) is 1.5. Don't think they changed it for the prototype

  24. Execellent weapon. My go to on patrol in Afghanistan when working with the Poles and Austrians(how we acquired them in the first place) from 06-12 over four tours. The flechette rounds are spectacularly effective compared to standard ammunition. Shots on target at high and consistent rate. Perfect room clearing weapon. Love it.

  25. So the projectiles would be leaving the barrel at around Mach 5. Which would probably have been a downside (aside from munitions procurement): It would make the rifle REALLY noisy.

  26. In science fiction, it's often assumed that future guns will consist of some sort of mini-railgun firing "micro-flechettes". So the projectiles may be TINY – like 1/4" long sewing needles – but it's firing so many, so fast, that getting hit would be like running your body through a sewing machine. Very different style of damage.

  27. As someone who used the AUG for quite some shots, I can tell you that the "Donut of death" is quite good for scoping. The max OPERATING range on the AUG is about 300m (sorry, no convertion to cheeseburgers per footballfield) and on this distance you can aim really well.
    So you can be sure that this scope is alsofine.

  28. I just bull-rushed the enemy and engaged in close quarters while in the canadian military, generally with my knife and ditched the C-7 POS i was given, 5.56 and 9mm parabellum are aneamic and underpowered cartriges… I have shot 308 in full auto and have to say you people just can't hold your recoil if you say its uncontrollable, and i would take my 44magnum over any little 9mm pea-shooter

Leave a Reply

Your email address will not be published. Required fields are marked *