Firearm Showcase: The Heckler & Koch G11 ACR, The US Army’s Lost Opportunity? – HIGH RES PICS!

In May of this year, I got the rare opportunity to travel to Heckler & Koch’s headquarters in Ashburn, VA, to take a look at some of the experimental and prototype firearms they have located there in their famous “Grey Room”. It wouldn’t be worth as much for me to just tell you about it and to snap a few foggy cell phone pictures, though, so I brought along Othais of C&Rsenal to help me take high resolution light box photos of these unique and rare firearms.

Previously, we looked at the Heckler & Koch G11K2 caseless ammunition-firing hyperburst rifle, which was cancelled with the fall of the Berlin Wall and the need to reconstruct East Germany. Today we’ll be taking a look at the version used in the US Advanced Combat Rifle program of 1989-1990, which explored then-new technologies that could form the basis for the next great leap in individual weapons for the 1990s. This was the last big hurrah for the G11, and the version of the rifle used for these trials is simply called the “G11 ACR”.

DSC_0878mod DSC_0874mod DSC_0875mod DSC_0877mod

In case you were wondering exactly what the inside of the G11 looks like, too, we also photographed a display model of the rifle’s mechanism, playfully labeled “Jim’s Toy” (I assume the name refers to Jim Schatz, the program manager for the G11 at the time):

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If you want to download all of these photos in their full resolution, you can follow this MediaFire link to a zip file containing them.

Nathaniel F

Nathaniel is a history enthusiast and firearms hobbyist whose primary interest lies in military small arms technological developments beginning with the smokeless powder era. In addition to contributing to The Firearm Blog, he runs 196,800 Revolutions Per Minute, a blog devoted to modern small arms design and theory. He is also the author of the original web serial Heartblood, which is being updated and edited regularly. He can be reached via email at


  • Seeing the mechanism I see why it was doomed to failure, at least for general issue use.

    • PeterK

      Seriously. It’s like a Swiss watch in there. Nice toy. Not so nice for combat.

      • Operational range 11,000 km

        The RS-24 Yars also known as Topol-MR (NATO reporting name: SS-27 Mod 2) is a Russian MIRV-equipped, thermonuclear weapon intercontinental ballistic missile first tested on May 29, 2007, after a secret military R&D project, to replace the older R-36 and UR-100N that have been in use for nearly 50 years. RS-24 is a missile that is heavier than the current Topol-M, and which can carry up to 10 independently targetable warheads.

        RS-24 has been deployed operationally since 2010. The RS-24 ballistic missiles would be the mainstay of the ground-based component of Russia’s nuclear triad and would account for no less than 80% of the SMF’s arsenal by 2016.

    • PK

      That’s an understatement, too. Seeing the old line drawings and tiny B&W pics, I knew why. Well, I thought I knew why… seeing these photos? I wouldn’t want to try to maintain that or troubleshoot any issues, and it’s fairly much my job to be able to do that.

      Something tells me you wouldn’t really want to be responsible for keeping one (or more) of these running, either!

    • Martin M

      It may not be as complicated as you think. We’re so used to see a firearm’s moving parts arranged in a liner fashion. The only part that stands out at as a problem for me is the meshing gears.

      • nova3930

        I think maintainability would be the issue. From what I see I darn sure don’t want Pvt. Anvil Breaker taking that apart for cleaning…….

        • Martin M

          Certainly not. Disassembly of those components are for Sgt. Screwup.

    • NATO response

      The T-14 Armata has been described as a major concern for Western armies. It is the world’s newest and most advanced main battle tank, as well as the first next generation tank to enter serial production. The tank’s main armament is twenty years ahead of comparable Western tank guns and renders existing NATO anti-tank weaponry obsolete.

      • 11b

        Is Putin’s troll factory striking TFB? Get outta here.

        • Giolli Joker

          T-14 is cool, though. 🙂

  • vwVwwVwv

    this is scify compared to modern rifles

  • PK

    The small B&W photos of the action, along with various line drawings, really didn’t do it justice. I’m delighted to finally see some detail!

    Same question as the SMGII, any plans to release uncompressed full res files at some point?

    • Is the zip file not working or something? I can upload them to Imgur if the quality in that zip file’s not right.

      • PK

        Oh, no, it’s working fine. They’re still compressed .jpg files with the usual artifacts, is all.

        Raw files from the camera would be bigger, but slightly more detailed… unless it’s an older DSLR, which may well be the case now that I think of it. I wonder if .jpg is the native file saved to the memory card.

        • Oh you want the NEF file, got it. Sorry, I am not very camera literate.

  • Giolli Joker

    I like that the super complex system is actually mostly made in mass production friendly stamped steel… there was clearly some R&D spent into making the thing ready for industrial manufacturing.

    • noob

      I’m told that the slab sided shape and olive drab color was to facilitate easy decontamination on the nuclear battlefields of western europe.

      I guess you don’t maintain or clean the G11. If you’ve used up three magazines and have not returned to somewhere where there is a G11 armorer then it is only a matter of time before you run out of liquid food to drink through the straw that is attached to your respirator. After that, your choice between taking off your gas mask for death by radiation poisoning, or starving to death.

  • Joe

    Yikes, where do you even begin to apply immediate corrective action?
    For giggles please refer to Demolition Man, only on-screen usage I’ve seen, although only as a prop for a “laser”.

    • PK

      I know that was a mockup G11, but I think it was the only film appearance overall. The armorer/propmaster probably liked the looks for a near-future sci-fi movie like that, and who could blame him?

  • Openmindednotangry

    Yah but Wesley snipes kicked ass with one in Demolition Man!

  • Jim N Jenna SK


  • oldman

    Thing that strikes me about this is it reminds me of traditional German craftsmanship. The problem is it also shows traditional over thinking as well. For common grunts on the ground there is one overriding requirement K. I. S. S. The less there is for them to think about the less that can go wrong.

    • Uniform223

      “K. I. S. S.”

      Keep It Short Simple or Keep It Simple Stupid, can go right out the window when a mischievous invisible sprite comes along and whispers into the ears of others.

      • oldman

        I was raised to believe in the three parts of Murphy’s Law
        1 If it can go wrong it will go wrong.
        2 Murphy’s Law is governed by Murphy’s Law.
        3 Murphy was a bloody optimist.
        That is why I believe in Keep It Simple Stupid.
        “Idiot proofing only proves an idiot can still find ways to brake it” The Great Book of Wisdom of the Cosmic Fortune Cookie.

      • Evan

        The Good Idea Fairy? She mostly talks to lieutenants.

  • john huscio

    Is or isn’t there a microchip in the g11?

    • It was the 1980s, microchips hadn’t been invented yet– computers ran on vacuum tubes and cogwheels.

      • ostiariusalpha

        All joking aside, the state of technology for integrated circuits even in the late 80’s would have made it pretty pointless to try to incorporate one into a practical firearm. All calculations done by the G11 are mechanical, and the answer set consists entirely of {pew; p-p-pew; pew, pew, pew…}, barring any malfunction.

  • jimmy craked corn

    I was told they never solved the cook of problem after a couple of magazines.

    • Quest

      No it uses High Ignition Temperature Propellant it propably rather melt the gun before it would cook of.

  • Interestingly, this one is marked at “45” on the selector, vs “50” in the above pictures. Did they reduce the mag capacity in the later version?

    Also, this video seems to show the weapon operating in a more traditional full auto rate of fire, as opposed to the original 2200rpm “hyperburst” debuted in the ACR program.

    • Irfan Zain

      Yes notice that they also show the hyperburst fire mode after that. Also, it shows the mechanics of how the magazine works

  • One of the issues that’s never brought up about the G11/Caseless ammo concept is the magazine.

    Due to the rectangular shape of the ammo, the magazine is a single stack. A single stack magazine that holds 50 rounds…

    If you look at some of the photos, the magazine appears to be about 15″-20″ long. So soldiers would have had to carry them like a quiver of arrows.

    • Giolli Joker

      True on the size, the rifle however holds 3 magazines side by side (live one in the middle).
      The sample in these photos has only a magazine inserted, the one in the previous article had the spare ones.

      • Very interesting! I did not know that about the spare magazines being kept in parallel.

        The specs list the G11 as 8lbs unloaded, and 9.5lbs loaded (1.5lbs per 50rd magazine.) So with 2 more mags, the loaded weight would be 12.5lbs.

        The weight of the magazines also brings up an interesting issue – the role of magazine weight in ammo carriage by the soldier.

        The 4.73×33 Caseless is billed as a tremendous weight savings advantage, weighing in at 1/2 the weight of 5.56. However when the weight of the exceedingly long magazines are factored in, the weight savings is far less dramatic.

        A loaded aluminum 30rd AR magazine weighs about 1lb (15oz w/ 55gr, heavier with higher weights.) A 50rd G11 magazine weighs 1.5lbs.

        210rd combat load: AR= 7lbs, G11= 6lbs (w/200rds)

        300rd load: AR= 10lbs, G11 = 9lbs

        600rd load: AR = 20lbs, G11 = 18lbs

        So when the weight of the magazines are factored in, the “weight savings” of the G11’s caseless ammo is essentially 1-2lbs per soldier maximum. Hardly seems worth the hassle, especially when you consider carrying those absurdly long magazines.

        • ostiariusalpha

          That 1.5 lbs refers to all three magazines being on the rifle. The individual mags were only half a pound.

          • So I went back to look up the specs. The 4.73×33 was billed as “1/2 the weight of 5.56″- which would put it at about 6 grams. Wiki lists the cartridge as weighing 5.2 grams.

            45 x 5.2g = 234 grams (8.35 oz). I don’t think it’s possible then that the loaded mag weighs 250 grams, as that would mean this 15-20″ long polymer magazine weighed 16grams ( basically 1/2 oz.) The magazine follower alone likely weighs that much.

            A Magpull 40rd is 9.5” long, and weighs 6.3 oz empty. The G11 mag is thinner then the Magpul, but it appears to be twice as long, and must have a substantial spring in addition to the weight of all that polymer.

            Assuming it weighs the same as the Magpul 40rd, the G11 45 rd mag loaded would weigh 14.66 oz – 0.91lbs. The 50rd mag would weigh 15.58 oz – 0.97lbs.

            That’s assuming that the mag weighs only 6.3oz empty – which, given it’s length, and the fact that polymer mags generally weigh more than aluminum mags, seems on the low end.

            I believe that the hidden weight of the magazines is why the HK G11 promo material shows the weight of the G11 with 2 magazines + 28 stripper clips, whereas it’s comparison with the M16 shows the M16 with 8 loaded magazines.

            This also is why I suspect the loaded mag weight may really be in the 1.5lb range, because if the 50rd mag was only 1lb loaded (per above calculations) it would still show a substantial improvement over the M16, and they would simply have promoted the G11 with it’s weight in loaded mags instead of stripper clips.

          • Giolli Joker

            We’re talking about prototypes with untested reliability and durability, however you are comparing a double stack magazine that hangs freely from the bottom of a rifle (where it can be victim of some abuse) to basically a thin, flat sided box that rests supported on its longest face and protected against impacts.
            The structural integrity of an AR (or AK or whatever) mag has to be considerably more than that of a G11.

            Given how much it is supported in the rifle, the G11 mag can be somewhat flimsy and the follower just has to be a flat piece of plastic separating the spring from the rounds (given the shapes involved, the need for a follower is even debatable).
            Bottom line: it can be much lighter than any known mag of comparable capacity because the design is totally different.

          • I just weighed a 50rd PS90 magazine, which is designed to run similar to the G11 and is similarly protected, and is entirely polymer with the exception of the spring. It weighs 5oz.

            5.7×28 shares a similar cartridge length to the 4.7×33, but is thinner. The double stack PS90 magazine is fairly comparable in thickness to what a single stack 4.7×33 would be. The PS90 magazine is made of very thin plastic – it is not nearly as thick and durable as a PMAG.

            The PS90 magazine is 10″ OAL. The G11 magazine is at a minimum 15″ long, but given the G11’s 21″ barrel length, it appears closer to 18″.

            If we scale the 5oz/10″ long PS90 mag to 15″, that mag would be 7.5oz. At 18,” it would be 9 oz.

            The gun was designed for WWIII. The magazines are designed to be repeatedly reloaded via stripper clips. Durable magazines are essential to the reliable function of semi auto weapons, much less a weapon with a 2200 rpms burst cycle (which likely necessitates a stronger, heavier spring.)

            The conclusion is inescapable -the empty magazine alone must weigh 1/2lb at a minimum, and quite possibly more as a 15″ magazine will require at least a 20″ long spring.

  • LazyReader

    HK fiddled with this thing for 25 years…………so let’s put this
    thing out to pasture. It’s a failed gun. Cool maybe, impressive certainly, but practical…hardly. It’s a fun oddity. But let’s not forget the fact they’ve yet to solve the problem of caseless ammunition reliability concerns in adverse climates. The G11 was the gun that bankrupted Heckler/Koch. They spent millions of dollars on it and when the Berlin Wall fell, the US left Germany with no market for a new combat rifle as the enemy to shoot em with had collapsed. The reunified Germany was dumped by a surplus of leftover AK-74’s sitting in warehouses.

    Not to mention it’s bigger brother, the HK LMG11 light machine gun with 300 rounds stored.

  • Giolli Joker

    EDIT: “Early prototypes featured one 50 rounds polymer magazine, while latest
    versions featured 45 rounds magazines – one in the loaded position
    within the movable housing and two spare magazines on the top of the
    rifle, asides from the loaded magazine.” (from world.guns. ru)
    I had assumed 90 rounds from 3 mags, it was from 2.

  • Hensley Beuron Garlington

    Thank you for sharing! Nice to see a video I haven’t seen before.
    I just now realized the ammo rides almost on top of the barrel. I believe that is an obvious reason for the caseless ammunition cooking off.

    • Irfan Zain

      I’m wondering if it would be more feasible to have all 3 of those mags joined in a large box mag like the LMG11 instead of 3 seperate magazines

      • Hensley Beuron Garlington

        I think you’re right. That larger capacity mags are always preferred if reliable and weight isn’t bad, especially for first contact. Could have the big box like mag on first and if empty, fall back on stick mags.
        I think a box magazine, like the P90 would be much better, along with rounded case proportions than the block cases used, and a nice, double walled, vacuum sealed plate between the action and barrel, and as much of the box magazine as possible, would eliminate the ammunition cooking off. You get insulation between the parts of the gun that get hot and the ammo and the ammo is less likely to transfer heat between each other as well with some gaps due to the round cases versus the flat sided boxes they were shaped like. I also think this would result in even higher capacities.
        I prefer the rear box compartment like the LMG11 though. I just saw a picture of it.

        • J Garcia Sampedro

          The ammo cook off was suposedly solved by Dynamit Nobel a few years after the G11 was axed, but nobody had enough financing available after the end of the Cold War to revive the project.

  • So I just did the calculations based on that chart:

    16.2 lbs = g11, 2 mags, 28 reloading units, 510 rounds

    g11= 8lbs

    4.7×33 = 5.2gramsx510 = 5.91lbs

    = 13.92lbs

    2 mags + 28 stripper clips = 2.28lbs

    Assume 1/2oz stripper clips (based on being clear plastic boxes) x 28 = 14oz (0.875lb)

    2 Mags = 1.4lbs / 0.7lbs per mag = 11.2oz per magazine

    Weight of loaded 45 rd magazine = (45x 5.2grams) + (11.2oz mag) = 19.4 oz / 1.22lbs

    Loaded 45rd G11 mag = 19.4oz

    Loaded 40rd Pmag = 22.6oz

    Loaded 42rd AUG = 23oz

    AUG vs G11 10 mag loadout

    G11 + 10 mags = 20.13lbs

    AUG + 10 42’s= 22.28lbs

    So when magazine weight is factored in, the G11’s caseless design offered minimal weight savings vs extended 5.56 mags.

    • Giolli Joker

      You count 10 magazines, but apparently the idea was to supply the soldier with no more than 3 mags + reloading units (as far as we know they might be just rounds somehow glued together).

      • No I looked them up, the reloading units (which are demoed in the video of the G11 posted in this thread) consists of a 15rd clear plastic box full of cartridges. The box is then inserted over the magazine, and pressed down, forcing the 15rds into the magazine in a single go.

        Based on their profile, 1/2 oz per empty reloading unit seems appropriate.

        I count 10 magazines because the reloading units, while clever mechanically, are pretty retarded.

        Assuming 2 45 round magazines, the soldier is only capable of firing 90 rounds total in a firefight, before having to then use 3 stripper clips per magazine to top them off.

        It’s as absurd as issuing an M16 with 3 30 round magazines, and then a bunch of 5.56 on 10rd stripper clips. It would absolutely save weight, but at a substantial reduction in combat effectiveness.

        The notion is even more absurd with the G11, as the entire point of the G11 is to fire it in 3-round burst mode for improved hit probability. That means a soldier equipped with 2 45 round mags has only 30 trigger pulls before he is forced to cease firing and resort to loading magazines under fire with stripper clips.

        If the goal is to carry more ammunition into the field for foot mobile soldiers then possible with 5.56, then that is based on the assumption of a heavy volume of fire/high threat level that the soldier is likely to encounter. Otherwise 240rds of 5.56 would be adequate.

        But then, if the foot bound soldier with the G11 is entering a high threat environment that requires firing more than 240 rounds, it seems a very safe assumption that he need more than 90 rounds on hand before resorting to stripper clips.

        Soldiers fighting in Afghanistan, against a far, far less advanced adversary then themselves, would never go out with 90 rounds in magazines and the rest in stripper clips.

        Considering the West German’s would be fighting at Ground Zero of WWIII, due to the Soviet control of East Germany, the notion that they would be repelling the far superior numbers of the Soviets (which prompted the need for carrying so much ammo in the first place) with 2 45 round mags and 28 stripper clips, is completely retarded.

        It amazes me that no one brought this issue up during the development of the G11.

        • Avery

          The magazine issue has bugged me as well. I heavily suspect the stripper clips were something from the original Gewehr-11 contract with the West Germans. For example, the Mauser entry used an internal 60-round helical magazine that directly fed from the clipazines (and a flip-up dust cover for the ejection/feed port would make it completely sealed). I’m certain that if the Mauser G-11 it would result in something akin to shotgun loading between full-auto bursts so you’d always had a fully-loaded rifle. I’m unsure if the “fully sealed” requirement resulted in the bizarre clipazine/magazine arrangement of the Heckler & Koch, but it sure sounds like it.

          • I really think the stripper clips were simply a way for HK to game the system to show a bigger advantage for caseless ammo in order to sell the G11 system, and mask the huge problem created by the magazine weight/length.

            At 5.2 grams per cartridge, caseless is truly lightweight; less than 1/2 the weight of 5.56. But once the mags are featured in, there’s only a 23% gain in ammunition carried.

            Per ~10kg weapon loadout:
            Steyr AUG + 10 42rd mags = 420rds
            G11 + 12 45rd mags = 540rds

            So while that is a net gain of 120rds, a 23% gain in ammo is not nearly as compelling as the 50%+ HK was trying to sell the Army on with their stripper clip system.

  • maodeedee

    But it’s ugly!!!! (It doesn’t even look like a real gun.