Metal Storm is a firearms engineering concept which revives a very old idea for the modern era.
The key to the metal storm is the use of superposed loads - several rounds of ammunition pre-loaded into a barrel like the charges in a Roman candle. The idea has been around for centuries - Samuel Pepys mentions a "very servicable" weapon of this kind that could fire seven rounds in sucession - but up until now the main problem has been control: how to fire one round at a time without the whole lot going off at once.
Metal Storm uses electronic ignition to fire the charges individually and each firing compacts the packing between it and the next to avoid a chain-fire. The individual loads are carefully adjusted so that each shot from a given barrel has the same ballistic performance despite their different barrel lengths etc. Due to the lack of moving parts to be cycled - indeed the lack of anything much apart from barrel and ammunition - Metal Storm weapons can be made light and can generate eye wateringly fast theoretical rates of fire: the company's demonstrator technology is capable of a once-off burst equivalent to 1,000,000rpm.
The system has its disadvantages of course - the most obvious being that it relies on a fairly significant industrial infrastructure: you reload the weapon by taking the barrel off and replacing it. The barrel is reloaded by sending it back to the factory. If you don't like the ammunition you've got in your weapon … tough. You can replace the barrel or you can put up with it.
On the same theme, although the risk of chain-fire seems to have been eliminated, one dud round makes all those behind it useless (or at least extremely dangerous to fire).
Then there's all that replacing of barrels … this would seem to require a significant bit of design work to ensure that the sights don't need to be re-set every time. Granted most modern machine guns do this all the time, but then they are machine guns and aren't called upon to be all that accurate.
There are all sorts of applications suggested for Metal Storm technology, many of which seem pretty perverse replacements for perfectly good conventional designs. Arguably the best role for it would seem to take advantage of the fully sealed, service free nature of the pre-loaded barrels which can be left unattended for a long time and then fired with little or no preparation, potentially with a very high burst rate. Some of these uses could include:
- Home Defence (competing with the revolver for a low maintenance weapon that the householder can grab in an emergency.
- Point Defence (generating a literal metal storm to protect vehicles from missile attack)
- Armament for remote automated systems (such as sentry guns or RPVs).
Game and Story Use
- These sealed, long life barrels could be a useful source of firepower after the end - potentially hundreds of years later if the propellant hasn't faded.
- More primitive examples of superposed loading could add danger and excitement to the lives of inventors in the pre-modern era.
- This can also be a good way of stopping your PCs looting weapons that you don't want them to have: "sorry lads, they were using pre-loaded Metal Storm style guns: all empty" or (in the case of robots) "the firing systems are built in and the replacement barrels don't fit your weapons"