Caseless Ammunition
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Basic Information

Caseless ammunition is an as yet largely theoretical development of the cartridge which seeks to dispense with the mass and engineering complexities of the cartridge case - if the case isn't there, the weapon does not have to go to the added effort of getting rid of it once the round is fired and the user doesn't have to carry it about in the first place. For reasons of sanity this category includes any fixed ammunition with a combustible case (because you would otherwise spend far too long arguing what's a case and what's just a coating of some kind on the propellant). It does not include separate ammunition like powder and shot or propellant reservoir weapons1, or things like railguns and coilguns which don't use propellant. Also excluded are pre-loaded weapons like those of the Metal Storm concept.

The problem with caseless ammunition is that, although it is heavy, expensive and a mechanical complication the case fulfills a number of functions that are tricky to complete without it. Amongst other things it keeps the round in one piece, protects the propellant from environmental damage and accidental ignition and provides a seal for the breech on firing. So far no manufacturer has yet come up with a workable solution to these defects that is cheap and robust enough to persuade a military adopter. The nearest was probably the Heckler & Koch G11, which was tested extensively by the Bunderswher before being written off as too expensive, insufficiently robust and likely to be too demanding to maintain2 - not all of these problems were due to the ammunition. At least one (relatively fringe) civilian weapon manufacturer (Voere) produces hunting weapons that consume caseless ammuntion but at present the design is a gimmick rather than mainstream technology.

Combustible case weapons are also mostly theoretical (at the small arms scale at least - they are more mainstream as ordnance) - the Steyr ACR is probably the best commercial example and this too is yet to be adopted by any large scale user.

During the Vietnam War, the US Army put in the field several M551 Sheridan tanks that used caseless ammo for the big guns. They were plagued with problems that showcased the fragility of the ammunition at the time, with many rounds cracking or breaking apart and being unusable. Further complicating the situation was the light armor of the Sheridan which made them vulnerable to man-portable heavy weapons. If they caught on fire, the caseless ammo they used (and all those broken unfired rounds sitting loose inside) were a major explosion risk.

But if it works

This is a gaming site, after all, and many RPGs already have futuristic or sci-fi elements, so there's no reason why we can't assume that at some point in the future these weapons won't be more practical than they are at the moment. Assuming that you can get causeless ammunition produced in a way that was both cheap and reliable, there could be several benefits:

  • The ammunition would be lighter, so a soldier (or vehicle) could carry more of it. This may make the difference in protracted battles.
  • The lack of metal used in the case is one fewer resource being expended on the infantry soldier, so it could help counter wartime resources shortages.
  • Electical ignition systems providing a faster rate of fire, and thus:
    • Increased suppression fire effectiveness because you're firing more bullets over time.
    • Increased accuracy against moving targets because there's less delay between trigger pull and bullet exiting the chamber.
  • Some of the more exotic chemical propellents used can result in the bullets travel faster (aka "increased muzzle velocity").
    • This further increases accuracy by because the trajectory of the bullet has less curve to it.
    • It can also result in more kinetic force at the impact, even with smaller bullets.
  • Smaller "cartridges" could mean more ammunition in each clip, so you won't have to reload as often.
  • Exotic propellents could be more stable, and be less likely to "cook off" if a troop carrier or arsenal caught on fire.
  • Less crime-scene evidence left behind as you don't have shell casings to worry about. In a more military / less criminal mindset, this would also make it somewhat harder for the enemy to gather post-battle intelligence on your troop compositions or amount of ammunition expended.
  • Ejected case is actually something of a nuisance in many situations - many designs of weapon eject their case in ways that can cause nuisance or injury to the user in some circumstances (many bullpup rifles eject in such a way as to hit the user in the face if they try to use it with the opposite hand to the one the designer intended, and even handguns are quite capable of putting hot case into an open shirt collar or the like) and extended firing can clog the weapon position up with spent metal (the miningun equipped AC-47D gunship was typically equipped with a number of snow-shovels for the removal of the drifts of spent case that accumulated inside the load compartment … sometimes this needed to be done whilst the aircraft was still in combat as the amount of material shifting about became a hazard to the crew and interfered with handling).


1. Wikipedia on Caseless Ammunition
2. Protodimension Magazine - issue #5 includes an article in defense of the existence/use of caseless ammunition in near-future RPGs
3. Caseless Technology a manufacturer's website about a specific caseless ammunition type
4. RPG: Cyberpunk 2020 - by default nearly all the guns in CP2020 fire caseless ammo, but the game certainly doesn't explore the ramifications

Game and Story Use

  • A caseless round leaves no ejected case behind - useful if you need a puzzle for detectives. Note that the same effect can be achieved by fitting a brass trap to a more conventional weapon.
    • In a game like Cyberpunk, you could go the opposite route. The unexpected presence of cases at the crime scene would indicate that the murder weapon is an antique, and thus likely fired by a collector (or just an older individual who may have had the gun stashed away for a long time).
  • Good for Sci Fi or twenty minutes into the future, as long as you can explain (or handwave) how the various problems were overcome. In the real world it may yet be a technological dead end, but in gaming it doesn't have to be.
  • Armament and equipment is yet another way to differentiate between factions within your RPG setting.
    • A more technologically advanced group might have figured out how to reap the benefits of caseless ammunition, and thus:
      • Have lighter, more mobile troops (though this would require some pretty crunchy movement or encumberence rules to matter, not one that usse the same base movement rate for everyone of a particular species) or vehicles.
      • Carry a lot more ammo per soldier, and thus the ability to stay in the fight longer. Again, making this matter in an RPG could take some GM finesse, as rarely do battles run long enough to start worrying about whose still got bullets, but in the case of a siege this could be a factor.
      • Be accurate to a greater range - this at least is easy to model (and make matter) in nearly all RPGs.
    • A group armed with the cutting edge weaponry might actually be at a disadvantage if there's a few kinks that still need to be worked out. If the caseless ammo results in more misfires or "cook offs" instead of fewer, that could be a problem for them. Not to mention some opportunity for the GM to work in some narrative flavor as soldiers explode around the PCs.
    • In a sci-fi setting, perhaps one world has the production facilities or natural resources needed to make the advanced propellant charges used in weapons manufactured across the quadrant. It's the best weaponry around, fast light and deadly accurate, but you have to import it at a great cost or danger. Other worlds, lacking the capacity to make such ammo, have to settle with inferior or alternate (lasers maybe?) weaponry.
  • In the real world, weapons that use caseless ammo are currently somewhat fragile, but the natural development of the technology being refined and perfected is expected to eventually result in the opposite. As a result, the GM (or RPG author) is free to decide where on that sliding scale the game's tech is at. Does the Rule of Cool make caseless the way to go, or is it meant as just another obstacle or bit of local color? Your call.
  • Exotic caseless ammo could be used as a play-balance mechanism for certain weapons. If a particular gun is a bit over-powered, you could dial it back by making the ammunition expensive, rare, or unreliable.
  • Mechancially, weapons that use caseless ammo could get bonuses on to-hit rolls, range, rate of fire, and/or clip size. These bonuses may or may not be offset by increased chance of malfunction on a bad roll.
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