Agback said:
It isn't. Its a multi-barrelled gun with a whole stack of caseless rounds lined up nose to tale in each barrel. The rounds are set of in very rapid succession by an electronic ignition system.
I read about it in 'The new Scientist'.
Whereas I read about it on sci.military.moderated.
Metalstorm has been around for a long time, generating the odd bit of hype at irregular intervals. The huge firing rate is slightly misleading, since it's basically just a lot of barrels strapped together and fired at once. Lots of bullets divided by a low activation time == big numbers.
IIRC Metalstorm's disadvantages include:
1) Ammunition resupply. After you've shot your load (IYKWIM...) you then have to reload all those barrels and that takes time. It also puts a strain on the logistics tail all the way back to the ammo dump.
2) Engagement times. The launcher is bulky, which means it's hard to slew and elevate.
3) Lack of a compelling application. There just aren't that many areas where you really need such a huge rate of fire; ordinary machine guns or autocannon are normally quite adequate. One application that's been mentioned is ship defense against cruise missiles, where you want to put up as many rounds as possible to create a "wall" against the incoming target. However, see 2) above.
Still, that 500,000 RPM figure makes for good copy....