Future Firearms Ammunition Technology 005: Caseless Ammunition – Lightening the Load, Pt. 3

Caseless rounds, left to right: 7.62x34mm Frankford Arsenal caseless, 5.56x24mm FA caseless, 5.56x25mm Hercules caseless, 4.7x21mm H&K/DAG early caseless, 4.7x33mm HK/DAG G11 caseless.

Previously, we discussed trying to lighten the soldier’s load by making the cartridge case out of different materials, including aluminum and compositing the case out of polymer and metal. Yet, wouldn’t the lightest possible case configuration be… Having no case at all? That’s the thinking behind one of the most ambitious ammunition configurations there is, the case-less round.

Of course, it’s true that before the metallic cartridge case was invented, essentially all ammunition was caseless, but today the term “caseless” refers to ammunition that is self-contained, but with a body made of combustible propellant that directly contributes to sending the projectile out of the gun’s barrel. This concept is as elegant as it is simple; after all, making every part of the round work at killing the enemy can only be a good idea, right? Well, it’s not so simple as that, because economically producing caseless ammunition suitable for automatic weapons has proven to be an incredibly technically complex challenge. For starters, there’s a fundamental contradiction to the concept: Gun propellants need to expose a certain amount of surface area to igniting flame in order to work properly and have the correct burn rate, but a caseless round needs its propellant to be consolidated into a single solid chunk which is durable enough for storage, shipping, and field use. This requires some kind of “disintegrator” charge – which may be provided by the primer – that breaks up the consolidated propellant during ignition, increasing its surface area. Also, caseless ammunition lacks any protective barrier between the propellant and the chamber, which may be very hot after a string of fire. This lack of a protective envelope reduces the threshold at which ammunition cooks off inside the weapon, a serious concern for a military small arm. Finally, caseless ammunition also cannot gain the benefit of disposable breech sealing that comes built-in to the modern metallic cartridge, so sealing must be accomplished some other way. All of these problems are difficult at low production levels, and impossible at the volumes required for a modern military round.

In fact, these challenges are so great that it’s unlikely that the concept will become feasible within the next few decades. However, if the considerable technical challenges are somehow surmounted, caseless ammunition offers the maximum reduction in ammunition weight possible with conventional projectiles, while also facilitating extremely high rates of fire, due to the elimination of the extraction and ejection phases of the cycle.

And maybe caseless isn’t so far out of reach, either. From the 1970s to the 1990s, German engineers at Dynamit Nobel, working with those at Heckler & Koch, developed an extremely mature caseless round that, while not yet ready for service, brought the concept the closest its ever been to reality. Perhaps my reservations are just cynicism, and a practical, reliable caseless automatic weapon is nearer than we think…

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 nathaniel.f@staff.thefirearmblog.com.


  • Ευστάθιος Παλαιολόγος

    “Next few decades” is a bid bold of a prediction… 🙂

    • I am happy for anyone to try to prove me wrong. 🙂

      • guest

        more likely never because of but not limited to:

        – much easier to cook off as it has no case

        – mechanically less reliable as it can be damaged during loading/feeding/carrying the ammo around
        – requires dedicated long-lasting gas sealing parts of a gun (good luck keeping erosion in check!)
        – can ignite easily due to static electricity and what not, while not in active use
        – same thing, this time as a general logistical problem
        – questionable methods of keeping combustion/pressure in check unlike conventional propellants that are formulated and shaped specifically to achieve a given pressure and pressure curve, here propellant has to “do it all”

        … and all that for a an insignificant reduction of overall weight of weapon/ammo carried. Transition from ceramic/steel trauma plates to HDPE/composite has probably had as much of a “lightening the load” effect, with little or no penalty.

        Is that enough for you Nathaniel?

        • roguetechie

          What makes so many people who comment here think that because Nathaniel writes about a concept that he endorses it or even wants to see it produced?

          Nathaniel is very much a reporter / writer in the traditional sense of these terms not a glorified OP/ed slinger or press release slinging typewriter monkey. His pieces aren’t about demanding that his preferred solution is implemented or trying to convince you of why his preferred situation should be implemented.

          He simply gives you the factual information, often a short summary of past current and future work in the field, and sometimes but not always his opinions on the subject with a few reasons why he thinks the way he does. It’s up to the reader to come to their own conclusions and research or discuss based on what he’s written and their own personal knowledge or feelings on the subject.

          It’s simultaneously funny, sad, and frustrating that he catches so much crap from a crowd that purports itself to be against group think and exactly the style of articles he DOESN’T DO.

          I love this and the other series of informative articles he does, they’re very educational and refreshingly free of exhortations to adopt the authors way of thinking or demands to accept his view on the subject.

          If you don’t like articles designed only to inform rather than tell you what to think, don’t read them.

          As for me, I’ll happily keep reading them doing my own research and thinking about things I wouldn’t otherwise

          • guest

            So to summarize your TL;DR, what we need is the TFB equivalent of a “safe space” where there is no criticism?

          • roguetechie

            No what we need at TFB is a place where the adults can talk, we have that place in Nathaniel’s threads. Really it’s fine if people want to waste their time crying and criticizing, because honestly many of us turn around and mock the living bejesus out of it privately which actually provides a good deal of the “fun” to these threads.

            Silly me, I was actually trying to be nice and explain to the group who just doesn’t seem to get the purpose of them as to exactly what the purpose actually is.

            As fun as it is to mock the usual suspects it would be way more fun if more people would actually participate constructively. As always, people are free to do what they like since either way those of us who enjoy these threads will continue to do so.

            TL;DR Why would I want a safe space when surfing the avalanche of stupid and butthurt is so entertaining?

          • guest

            You just degraded this discussion into a “diss” a-la-40+-year-old-white-male-from-the-90’s haven’t you? You at least tried, I’ll give you that.

          • I sincerely appreciate the support, rogue, but it doesn’t bother me, honestly. If anything, I like that I can write stuff that’s not just meaningless clickbait but that still capture’s people’s attention, even if it does so in the “wrong” way.

            And anyway, I’ve always treated reading the comments section a little like stepping into the ring. People are very opinionated and that’s OK.

          • roguetechie

            Lol, thanks man.

            I was actually trying to be helpful, because so many users seem confused about why these posts are written and somehow think that the various approaches are being endorsed or suggested.

            On the flechette ammunition article I always found it interesting how the Russians took it a completely different direction.

            For example the AO-27 and the big boy dragunov super flechette.

        • I think if you read what I wrote more carefully, you’ll find I was saying the polar opposite of the position you were responding to. Here’s a quote:

          “In fact, these challenges are so great that it’s unlikely that the concept will become feasible within the next few decades.”

          So when I say someone should “prove me wrong”, I’m really saying “feel free to get to work”.

          • guest

            Yeah, and that’s exactly what I am responding to. The whole concept of caseless ammo is such an epic fail that the assumption of it ever being adapted is flawed, as it entails the *possibility* of actual adoption and use. And that’s exactly what I responded ment when I listed the chronical flaws the ammo has… and will for the most part forever have.

            Caseless ammo, fletchette ammo etc are all from the very same department of wishful thinking and detachment from reality as flying cars: yes, can be done, yes, technology does make advances that to some degree patch up the flaws. But no, when one takes up the complexity of the vehicle and starts talking about autorotation and what not that they do not posess, it all crumbles.
            Same thing here.

          • Which is why no one should ever discuss them. Got it.

          • guest

            No, you spoiled little kid, you can talk about whatever you want from sandcastles to pokemons for all I care. But if you are making articles with overly clickbait titles “xxx… of the future” and receive criticism you should at least not run away. But for all I care, please do.

          • Sounds like something’s gotten under your skin, not sure what it is.

            I’ve been accused of clickbait for everything from deliberately attention-getting titles to “Colt won a contract”, so if I seem unimpressed by accusations of that sort, then I guess I am.

            Not sure how I am “running away”, either, that seems to be wishful thinking on your part.

  • cwp

    Nathaniel, what’re your feelings on the Italian 9mm AUPO semi-caseless round?

    • It’s an interesting idea; I may cover it under “expellable” ammunition.

      • Kivaari

        Didn’t S&W also try an electrically fire variant in the M76 SMG?

  • TechnoTriticale

    re: …storage, shipping, and field use.

    And field use includes among other things, being credibly waterproof, to MIL-STD-810G at a minimum: water submersion to 1m for 30min (which doesn’t seem adequate for amphibious units).

    Low-no residue (including primer debris), and especially nothing still smoldering is another challenge.

    We might get individual directed energy weapons before all the problems can be solved.

    • KestrelBike

      Sweet, another demolition man prophesy comes closer to reality.

    • Isaac FluffyWolf Rader

      I’ve seen a guy make actual functioning laser pistols in his spare time, so you’re right on the money there.

  • imbecile

    There are very old and effective caseless sealing methods in artillery, like the Welin Breach Block. Someone had to have tried that in smaller calibers.

    Also I think, the progress that had been made in electronics and actuators in the last few years could vastly improve the viability of caseless ammunition, like it could become possible to have a solid block of 5×20×10 rectangular rounds with no empty space and reliably take that apart and feed it into a chamber.

    And lastly, since caseless lends itself to electric ignition, when you combine that with the fact that you don’t need to eject, you can rearrange guns quite drastically. Like a pistol with an extremely low bore axis, because the barrel goes between trigger finger and middle finger, and the trigger is above the barrel. Obviously only for small calibers and with proper heat insulation. Or bullpubs where the ammunition is a block in the butt, and you can have any trigger you want, because transmission is electric.

    • Kivaari

      Greased felt wads and rubber gaskets were tried in the 1860-70s.

    • ostiariusalpha

      All firearms need to be capable of ejection, if only for simply emptying the chamber to make the weapon safe. Beyond that, stoppages happen, and you need to be able clear them up quickly.

      • imbecile

        Yes, ejection is needed, but there is a difference between having ejection as part of the normal cycle, or as a recovery. When it is as a recovery, there are a lot different usability and ergonomics constraints, you can expect the user to change the grip or open a hatch or something like that, things that are unacceptable if they had to be done on every shot.

  • Pete Sheppard

    Then there are combustible cases, like the 120mm tank cartridge. Kind of like the best of plastic and caseless. Reducing the concept to small arms size and usage seems to be another nice, but currently impractical idea.

    • Kivaari

      The sealing system, gasket, has been used since WW2 when the Germans adapted a small cannon to fire the rockets from the Panzerschreck 88mm. The Puppchen Racketenwerfer 43 simply added a case head to the rocket and the round fit into the converted cannon. It gave extra range but certainly didn’t achieve caseless levels. That is similar to our 120 mm cannon.

  • Kivaari

    I understand one of the NATO tests that none of the cases less ammunition has made it though, if they even got that far, was the pallet load being hit by a NATO standard 20mm HE round. What happens was reported to be a big blast instead of a burn. Conventional ammo catches fire and burns up whereas G11 ammo, in particular, went high order.

  • valorius

    I want modern rocketball ammo, that’d be really cool 😀

  • Blake

    Apparently the US Army experimented with propane/natural gas-fired artillery during Vietnam. The main problems they had were:

    – shot-to-shot inconsistency due to incapability of metering out the precise volume of gas required to maintain a given trajectory
    – shot-to-shot inconsistency due to temperature variations, both of the ambient environment & the gun itself after shooting a few rounds & heating up

    Seems to me that modern automotive computer-aided gas injection technology could probably solve these problems with the right sensors, but miniaturization to the extent that such a system would be competitive with modern battle rifles would likely be a significant challenge…

    • B-Sabre

      I believe one of the proposals for the FCS field artillery kit was a liquid-propellant gun, using the sort of technology you mentioned.

  • marathag

    Like fusion power, just 15 years away for the past 40 years

    • Paul Joly

      No because firearm using caseless ammo is something that come and go in the firearm sector. (musket, paper cartridge, grenade…)

  • Giolli Joker

    I wonder if the option of going back to having separated charge and projectile would work…
    Something on the line of PCP air guns but with a combustible fluid (or several ones getting mixed) instead of air.
    With an integrated system like TrackingPoint maybe one could even calibrate the amount of propellant needed for the particular shot.
    I think that the basis of such a concept (with solid charges) are already in use with some automated howitzers and naval cannons.
    Of course there would be several challenges to be faced, but not many more than with caseless rounds.

  • jerry young

    We might as well go back to muzzle loaders, this is as dumb and impractical as it gets just in the name of saving a few grams of weight! the case makes ammo weather proof convenient to carry easy to load, reload and store able for long periods of time, without the case in my opinion ammo will be more susceptible to damage from weather moisture friction and impact if the charge starts chipping away at the very least you would lose velocity and could end up causing squib loads or could fail completely, there would have to be a way to store and transport this caseless ammo such as a case adding back the weight you saved so whats the point, not to forget firing ammo makes a gun dirty the case protects the chamber from most of this and from damage that means you would have to clean the chamber often and what about live burning embers that may remain that could cause the next round to prematurely detonate, also when ammo is fired the case expands to fit the chamber sealing in pressure and directing gasses forward without the case there would be space around the caseless ammo that would allow the expanding gasses to go rearward the bolt would have to form a seal not too easy when the gun gets dirty, there are just too many negatives to this idea, great idea for a hit man in a movie no case left at the scene of the crime to pick up

  • Iggy

    I’ve always thought the Dardick tround concept is just be just begging to be adapted for caseless ammunition. It’s an incredibly simple system compared to a G11 (which I’m pretty sure can also be said for some mechanical watches) and the rotating chamber could allow for a system that taps some of the firing mechanism to send a burst of air through the empty chamber after firing to clear out any debris though the ejection port, Also it allows for ejection if you get a dud. But of course there’s still a few issues that need to be sorted out.

  • Badwolf

    I’m guessing the problem of storage and shipping can be solved using sealed disposable mags. So you make it the mag’s job to protect the rounds from contamination. But that doesn’t help with the other issues such as cook off, etc.

  • SlowJoeCrow

    I think liquid propellants may be a better direction since they avoid some of the problems of caseless. Although it doesn’t have the precision needed for a bullet, the Paslode Impulse cordless nailgun is a successful proof of concept of a liquid propellant system that has been around for over 20 years.

  • Isaac FluffyWolf Rader

    I actually did a research paper on this once – apparently there were a lot of other problems, such as the propellant possibly being screwed up by your touch, and also that the G11’s ammo was carcinogenic.

    And also there’s heat management problems.