In fact this idea is not that futuristic. The Russian secret services made us of three shot "Troika" pistols. These resemble "powder and ball" muzzle-loaders with the charge fired by a 9 volt battery. It's surprising that the barrels were not made as a captive piston design to reduce the firing signature.
The above pages reminded me of an idea I'd come across for a disposable sub-machine gun.
I've only a vague idea what you'd use a disposable sub-machine gun for, but do have some suggestions as to the form this might take:-
The weapon would be designed so that it was its own shipping container, rather like a M72 LAWs launcher. Like the LAW the outside is printed with clear instructions. When the weapon is opened out the sights pop up, the pistol grip unfolds and the mechanism is cocked or armed. Alternately this could be a folding design,
If the weapon is closed up again the mechanism is uncocked. There are several ways to achieve the latter, but the most likely is that the firing sear is part of the bolt retraction mechanism and aligns with the trigger mechanism when the weapon is fully opened out.
The muzzle and ejection port are sealed up until the first round is fired.
Magazine capacity will probably be between 50 and 65 rounds. The configuration that I suggest is for the rounds to be held in a helix around the barrel, a variation of the system used with the Bizon and Calico weapons.
This would give a very compact configuration. It may be possible to use gas collected at the muzzle to drive the helix, thus avoiding tired springs after a long storage.
To reduce weight rounds would use aluminum casings. Polymer or caseless rounds may also be possible. In a throwaway weapon, you could get adequate caseless obturation using a metal-rubber laminate bolt head. Since the weapon is disposable this doesn't need to last more than 100 or so rounds.
Calibre of this submachine gun is something to ponder. Since the weapon would not be reloaded in the field calibre choice is not so dependent on logistical considerations. Any round can be used providing it will work with a simple blowback mechanism. A .45 round would give the best stopping power, while high velocity 7.63mm rounds would give a flatter trajectory and good penetration. Rimless versions of .22LR and .22 Magnum are also possible. It is most likely that the disposable SMG will be 9mm calibre. The few countries that do not manufacture 9x19mm (Parabellium) rounds manufacture 9x18mm (Makarov) instead. Cyclic rate of the weapon is another thing to consider. My feeling is to opt for a rate of around 450rpm. While this is a lower rate of fire than most modern weapons this still translates as 7-8 rounds per second. 450rpm was the rate of fire of the M3 Grease gun. This weapon only fired fully automatically but it was quite possible to fire single shots with competent trigger control. This suggests that the disposable SMG may not need a selector mechanism. The proposed construction of the disposable SMG would allow the use of a pneumatic rate reduction mechanism rather like that used with the Suomi SMG. A possible use for this weapon might be as a survival and self-defence system for downed pilots. This might suggest a 22 weapon, though 9mm Suomi were used for hunting in the Third Finnish Independence War. For hunting a single shot mode may be necessary.
Uses for Disposable SMGs
Having the weapons as survival/self defence systems has already been mentioned. Part of the strategy for the design I've described gives the weapon a long shelf life, so it could be issued as a standard munition for vehicles and aircraft.
Disposable weapons may be carried by Backpackers and Hikers as "insurance" should they become lost. These would be semi-automatic weapons loaded with .22LR semi-hollowpoint rounds.
Another use that occurs to me is as a home defence weapon. In this guise the weapon will probably be semi-automatic. To reduce the danger of rounds penetrating walls and endangering innocents the rounds would be .40-.45 rimless shotshells.
Disposable SMGs would also see applications for clandestine force. In this mode the weapon would have a simple integral suppressor and be loaded with heavy sub-sonic rounds. A simple "brass catcher", such as a tube of stocking would be added to this model
My friend Ed comments further:-
"I can imagine sending SEALs ashore with a few. A weapon you weren't expected to bring back would be very likely put to use. Probably it could be rigged as a booby trap, like the old anti-poacher weapons.
The shot loaded home defence weapon is one cool idea. Such a weapon could be made child-safe at least as easily as an ordinary gun. (The brats wouldn't be as inclined to mess w/ a dull-looking package in any case.) A smoothbore would cost less than a rifled version. For all I know, a military version could be smoothbore too; we're only talking about 100 m effective range.
It occurs to me that a Disposable SMG could be built using multiple barrels and superposed loads, in the manner of Metal Storm but dispensing with the fancy-schmanzty electronics: a pull of the trigger touches off one barrel-full of rounds. A cluster of 25 bbls each holding 6 rds = 150 shots. No brass means less weight and, of course, no ejection. Crude perhaps, but with emphasis on sophisticated materials to save weight it would be a lot of firepower. You could even buckle one onto an assault rifle using the grenade launcher rail. By sophisticated I just mean high-strength plastic/nylon for most parts and (I hope) alum alloy for the bbls. But I've had a think about doing away w/ the electronics, and realize that that might not be 100% workable. I suppose you could fire a squib to start each bbl firing. A couple of flashlight batteries would be enough for power, but you'd still need reliable switching. Still, if our Metal Storm man really has learned how to make a bullet work as a gas check, it should be possible to meter a tiny amount of gas backward to ignite the next round. A Roman candle effect is sufficient for a kleenex gun of this sort.
If such a weapon worked, I'd make it an odd caliber, 9.7 mm, or 11.8, or some such, so that the discarded bbls couldn't be easily reused.
Another possible idea for a disposable gun is the Disposable Revolver. This would have a six to nine round polymer or Aluminum cylinder built rather like that of 19th century "Cap and Ball" revolvers. In other words the chamber would contain loose powder and be plugged by a bullet at one end and a primer at the other. In fact it may be more apt to think of the cylinder as a multi-shot cartridge. The cylinder would be sealed within the gun's body and be water-tight until the first round has been fired. This casing would be transparent and the cylinder marked so the shooter can see how many shots he has left. A weapon of .38spl/9mmP power level should be practical, in which case I'd make the standard load a heavy soft lead bullet. 200gr bullets worked well in the British army's .38 revolvers and there is also the possibility of using heavier bullets manufactured for medium calibre rifles. Given the construction of the weapon and that the bullets are likely to be subsonic it would prove very effective if used with a silencer.
A smaller calibre version that would serve as a vest pocket gun should also be possible. This will most likely be a mini-revolver firing a small calibre high penetration round such as the 5.45 PSM.
Ed has suggested that useful feature for such small calibre pistols would be the ability to fire more than one round at once. The only way I can visualise doing this for this type of weapon is by making the axis pin of the cylinder a second barrel, so the first pull of the trigger fires two shots, then the gun fires single rounds for subsequent pulls of the trigger. Heavier bullets such as the 53gr 5.45mm and 55-62gr 5.56mm designed for rifles may give better penetration from such short barrelled weapons.