Foom! Remotely piloted platform spews out grenades

at the U.S. Army's Picatinny Arsenal. For the demo, ballistics maker Metal Storm Ltd. of Australia put its firing system on a robotic vehicle made by Foster-Miller Inc. of Boston (www.fostermiller.com).

The demonstration included the remotely controlled firing of stacked pyrotechnic and inert rounds from a fourbarrel pod with a recoiling system. The firing system has no mechanical parts and carries a payload of 16 shots, 10 more than the existing alternative, Metal Storm says. The system can fire grenades at variable rates. “We intend to undertake further development of the Metal Storm system to increase the payload to 48 shots,” said Metal Storm Director of Scientific Innovation Mike O'Dwyer.

The firing rate of conventional mechanical weapons is generally limited by mechanical actions which must complete between each firing. For instance, some mechanical Gatling gun weapons can fire at approximately 6,000 rounds/min. Metal Storm weapons contain no mechanicals to slow the rate, and this has resulted in demonstrated burst rates in excess of 1 million rounds/min from a 36-barrel weapon.

Metal Storm's technology hits superhigh firing rates by stacking numerous bullets in a barrel, with each bullet separated by a propellant load. The leading propellant can be reliably ignited to fire the bullet, without the resulting high pressure and temperature causing unplanned blowby ignition of the trailing propellant load, and without collapse of the projectile column in the barrel.

What makes this concept possible is the invention of a bullet which expands and locks in the barrel in response to high pressure immediately in front of it. As a consequence, each bullet can fire in sequence from the barrel. A barrel tube is a complete weapon once loaded with rounds. It has no ammunition feed or ejection system, breech opening, or any mechanical operation whatsoever. The only moving parts are in ancillary mechanisms such as recoil-control systems, target-acquisition systems, and turreting platforms. Bullets stacked in the barrel alternate with the necessary volume of propellant. One potential problem, though, is that if the propellant loads are of equal volume and bullets fire in sequence, the barrel length will effectively increase as firing progresses. The muzzle velocity of later bullets will be greater than the muzzle velocity of those fired earlier in the stack.

Metal Storm gets around the difficulty by graduating the propellant volume and/or type to produce a similar muzzle velocity for each projectile. A projectile stack can be specifically loaded with calculated propellant volumes. This lets the company tweak the concentration of kinetic energy for bullets fired at a predetermined rate and range.

Each load of propellant contains a primer. Primers connect to an electronic fire-control system. When firing, an electric signal goes to the appropriate primer which then ignites the propellant to fire the bullet.

Video clips of the Metal Storm/Talon demonstration are available for viewing on the Metal Storm Web site at www.metalstorm.com/