Caseless ammunition demo action

The US Army (as well as other armed forces) has experimented with a bunch of interesting arms design ideas, and one that keeps coming back to the surface is the use of caseless ammunition. The basic idea is to form gunpowder into a solid block and embed a primer and projectile into it. This offers several theoretical advantages over standard cartridges:

  • Lighter weight ammunition
  • No chance of ejection-related malfunctions
  • Fewer operations in the firing cycle, allowing a higher cyclic rate

It also has a couple theoretical problems:

  • More heat retained in the action (instead of being ejected in the form of hot brass)
  • Potentially fragile ammunition
  • Greater likelihood of cookoffs
  • New mechanism needed to seal the breech (with standard ammo, the brass case expands on firing to provide a gas seal between the powder and bolt)

Despite numerous experiments, most notably the Heckler & Koch G11, the advantages have never been able to outweigh the disadvantages. But that doesn’t stop the idea from being pretty intriguing. We had the opportunity to take a look at a demonstration mockup of a caseless ammo rifle made by the Hughes company. Hughes is best known as an aircraft manufacturer, but also did a lot of weapons work, including designs like the Heligun (lots of aircraft-to-guns spillover used to happen – like Fairchild and the AR15). Anyway, this caseless demonstrator is pretty neat, so we put together a video for you:


  1. With the materials and chemical compounds currently available it is impossible for this type of weapon work. the sheath retains nearly all the heat that convey the gases generated in the shot. on outward sheath also expel the heat. cooling is currently the biggest problem of weapons and no one seems able to solve. Aggravate an intractable problem is not the best policy.

  2. What type of material seals the breach block to the chamber? It would have to be hard enough to resist wear but soft enough to seal. This makes me think back to paper cartridge rifles such as the Chassepot that used rubber gaskets, I believe, to seal the breach.

  3. Ian, you may want to take a look at the Steyr ACR – that uses the same “rising breechblock” concept, but with a cased cartridge (and some other weirdness).

    Anyway, to answer some questions…

    Caseless cartridges usually use fully combustible primers.

    Yes – twice.
    Mechanically, there was the Steyr ACR I mentioned above.
    Before that, Steyr was working on a rifle for Usel cartridges (elecritcally-primed caseless), but decided it would require to much development to make the ACR deadline.

    @Justin Finney:
    Apparently Voere used steel in the VEC-91 (from the patent application: “The angle between the two generatrices can be within the range of to, and depends inter alia on the elastic deformation dimensions of the material used for the seal. For the steels usually used in weapons production, the angle is preferable This has given especially good results in practical tests. “)

  4. Turns out there is a gun that fires cased ammo and operates in a similar manner. The TKB-022 used an annular gas piston just like this demo model to move a vertically sliding breech block down to unlock just like this demo model. The weapon was never adopted but it was an interesting concept and one of my favorites that never made it.

  5. Forgotten weapons, are you hiring? I would work for less than minimum wage to do what you get to do. I’m very envious.

  6. I wish I had caught this sooner, but that system looks very similar to the system H&K cooked up for their caseless PDW they planned to follow-up on for the G11. As well, it the drop-down breech-block, dual-piston system was used on the ARES AICW, as well as a similar system used for the LSAT (although that uses a rotating breech-block)

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