In a project I’m working on, I’m looking at what the characters imprisoned in a space habitat can do with old technology. That habitat is a Prisoner of War camp. Their captors don’t want them have weapons. Picky, picky.
Said captors have blasters, high-tech energy weapons. Our heroes need an equalizer. They have access to a workshop, at about 50’s tech level. I looked at conventional firearms, which are after all the standard for good reason. If you are looking at being self-sufficient, that doesn’t work. Epiphany here. The ammunition is the weapon, the gun is the delivery system.
If you want reliable firearms ammunition, and plenty of it, you aren’t going to do that in a small workshop. It took generations of work, from the original flintlocks to modern day, to master the arts and skills and build the infrastructure to make small arms ammunition at scale. So, how about air guns? The first military air rifle was fielded in 1780, and had some distinct advantages over single shot muskets, such as being able to fire 22 .46 calibre balls on a single charge.
The virtues of a military weapon are that it be reliable, cheap and deadly, in that order. The Girandoni didn’t cut it on the first two. It required a lot of TLC to function reliably, and it was vulnerable to the knocks and bumps of infantry service, restricting it to elite sniper units. It was decidedly not cheap. The precision required strained the precision technology of the day, requiring highly skilled craftsmen. The assembly line hadn’t been invented yet. It was reasonably deadly. The ballistics were approximately equivalent to the modern .45 ACP. Deadliness is easy.
Firearms, which got rapidly better, did have all three of those virtues, pushed the airgun into niche applications such as bench shooting.
A technology which never caught on was the rocket gun, which first emerged as the Gyrojet of the 1960’s. It saw action in Vietnam, but never caught on because it failed the RCD test. The US Army tested it, and kicked it to the curb.
My cast of characters includes highly skilled engineers who understand military requirements just fine, thank you very much.
To give me a feeling for just how hard it would be to design such a weapon without modern CAD software, I did most of the design calculations with a slide rule. Here’s the end result.
Rocket Round RCD-1 Pistol
Dry mass: 8.5 mm [^1]
Wet mass: 11 grams (booster adds 5 grams)
Terminal velocity: 330 m/sec (at 3 m from muzzle)
Kinetic Energy: 462 joules (approximately the same as .45 ACP)
Propellant: Doped KNSU, 95% H~2~O~2~ booster charge.
RCD-1 Rocket Pistol
Box magazine, 8 rounds.
Double action only. Pulling the trigger chambers the round and fires it.
Electrical ignition for both booster and round. Magazine safety, opens firing circuit.
Grip safety, for both right and left handed shooters. Again, opens the firing circuit.
Inserting mag compresses spring, which provides energy for the firing circuit.
Spring has enough energy left after firing to eject magazine.
Muzzle velocity 50 m/sec. Terminal velocity 330 m/sec.
Weights:
Empty, with magazine, 500 g
Loaded, 600 g
Significant firing signature. Puff of steam from the muzzle, 3 metre smoke trail.
Penetration as for .45 ACP FMJ. Right through a human body, several centimetres of wood or composite, sheet metal.
Can defeat blaster armour, which is largely designed to absorb heat/electrical energy.
Weapon itself is similar in size and appearance to an M1911 Colt, but masses less than half as much, with negligible felt recoil.
Rocket Round RCD-2 Carbine
Dry mass: 10 g
Wet Mass: 23.4 g (Booster adds 5 g)
Terminal velocity: 850 m/sec (at 3 m from muzzle)
Kinetic Energy: 3600 J (Comparable to 7.62 x51 mm NATO)
All up Length: 60 mm
Atmosphere version has folding fins.
Vacuum round uses angled nozzles. Generally considered less accurate than fin model.
RCD-2 Carbine
Pistol and rifle ammunition are not interchangeable.
Box magazine, 15 rounds.
Double action only. Trigger pull chambers and fires a round.
Electrical ignition for both booster and round. Magazine safety, opens firing circuit.
Manual safety, right and left handed. Again, opens the firing circuit.
Inserting mag compresses spring, which provides energy for the firing circuit.
Spring has enough energy left after firing to eject magazine.
All up mass, empty: 2.25 kg (4.95 pounds)
All up mass, loaded: 3.1 kg (loaded magazines 850 g each) (5.85 pounds)
The Requirements to Build It
The materials needed for such a weapon are significantly less challenging than a convention firearm. The barrel can be a light metal tube. There’s no need for slide to eject the fired round, because the entire round goes out the barrel.
The rocket fuel is made of potassium nitrate and sugar. Amateur rocketry enthusiasts have polished that formulation to a high gloss.
For the booster, propellant grade hydrogen peroxide can be made on a small scale with minimal equipment. It needs to be in a rugged casing, with no materials that could act as a catalyst. An electric pulse will ignite it.
Let’s make very clear here that this is a fictional concept. I haven’t, and to my knowledge no one else has, done a design like this since the 60’s. I haven’t, and I’m not going to. If someone did, it would be very hard to regulate or control.
Public Domain
All the foregoing is specifically released to the public domain, to be used however you want. So, if you want your characters to load and holster, feel free.
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