Metal Storm Limited (ASX : MST) is a research and development company that specializes in electronically initiated superposed load weapons technology. Metal Storm is both the name of the company and the technology.
The company is based in Brisbane, Australia with a subsidiary in Arlington, Virginia, U.S.A. Metal Storm owns the proprietary rights to the electronic ballistics technology invented by J. Mike O'Dwyer. The company has over 30 worldwide patents covering aspects of ballistics technology.
The concept of stacked projectiles (multiple projectiles loaded nose to tail in a single gun barrel with propellant packed between them) predates Metal Storm. Roman Candle, a traditional firework design, employ the same concept. However, in the case of Roman Candles the propellant which propels the leading projectile from the barrel continues to burn in the barrel, igniting the charges behind each subsequent projectile in turn, ensuring that all projectiles in the barrel are discharged sequentially (and inevitably) following from the single ignition. Various methods of separately firing each propellant package behind stacked projectiles have been proposed which would allow a 'single shot' capability more suitable to firearms.
Mike O'Dwyer, an Australian inventor, observed that these methods did not eliminate the problem of unintended propellant ignition caused by hot gases 'leaking' back up the barrel. Mike O'Dwyer's original Metal Storm patents demonstrated a method whereby projectiles placed in series along the length of a barrel could be fired sequentially and selectively without the danger associated with unintended propellant ignition.
In the original Metal Storm patents the propellant immediately behind the projectile closest to the muzzle of the gun barrel was ignited by an electronically fired primer, the projectile was set in motion, and at the same time a reactive force acted on the remaining stacked projectiles in the barrel, pushing them backwards. By design, the remaining projectiles would distort under this load, expanding radially and sealing against the gun barrel wall. This created a seal which prevented the hot propellant gases (expanding behind the lead projectile) prematurely igniting the remaining propellant charges in the barrel (blow-back). As each of these propellant charges was selectively (electronically) ignited, the force 'unlocked' the projectile in front and propelled it down the gun barrel, and reinforced the radial expansion (and hence the seal) between the projectiles remaining in the barrel and the barrel wall.
Subsequent designs discarded the 'distorting shell sealing against the barrel' concept in favor of containing the propellant in 'skirts' that form the rear part of each projectile. These skirted projectiles differ from conventional 'shells and cartridge' units in that the skirts are part of the projectile, and in that the skirts are 'open-ended' (at the rear). The rearward seal to the skirt is provided by the nose of the following projectile in the barrel. As in the previous design, the firing of a projectile results in a rearward impulse on the remaining projectiles stacked in the barrel. This results in the skirts of the remaining shells in the barrel being compressed against the following shell heads, effectively creating a seal that prevents hot gases in the barrel triggering unintended propellant ignition ('blow-back') along the length of the barrel. Metal Storm also introduced inductive electronic ignition of the propellant, effectively from outside the barrel. This overcame technical issues in maintaining physical contacts with the propellant charges, which due to the compression effectively 'shift' slightly backwards within the barrel during firing.
The skirt-to-nose joint has in recent designs incorporated an easy-release arrangement which allow the shells to be clipped together to form robust ammunition 'tubes' which can be transported more readily than individual shells, and inserted directly into Metal Storm barrels. Metal Storm have indicated the tubes can be 'pulled apart' and reconstructed in the field to make up custom combinations of ammunition, and to facilitate 'topping up' a partly discharged tube that is still in the barrel.
The distinguishing features of this technology are the absence of ammunition feed and, casing ejection systems (the only moving parts are the projectiles), and the electronic ignition of the propellant charges. The relatively simple external shape of the Metal Storm barrel allows for the clustering of Metal Storm barrels into a barrel array or 'pod', or for their attachment (as single units) 'bolted on' to existing weapons mounts, including infantry weapons. The absence of a mechanical feed mechanism and the inherently compact lightweight nature of Metal Storm systems also makes them suitable for attachment to light robotic ground and aerial vehicles. The electronic ignition allows for the firing of the stacked ammunitions at 'electronic speed' without any delays caused by mechanical ammunition feed mechanisms. The electronic firing also creates the potential for tighter integration with electronic targeting systems, with electronically programmable fuses in air burst ammunition, and with (in the case of hand guns) electronic grip recognition technology.
The clustered barrel array has been further developed with the design and building of prototypes of electronic firing control systems, allowing selective firing from any barrel in a cluster, and within each barrel the ability to control the rate of fire. This allows for responses which range from the equivalent of a volley gun discharge (all projectiles 'at once') to using (selectively) individual munitions with increasingly serious (but non-lethal) effects and lethal munitions including high explosive and air burst shells (all from different barrels in the array). The ability to deploy a range of munitions from effectively 'one' weapon system, and to selectively escalate responses from the non-lethal to lethal without reloading, has been put forward by the company as an advantage in urban warfare and insurgency situations where a range of responses may be quickly required in close quarter fighting and crowd control.
A patent exists for a design where the gun tubes at the edges of the array are angled outwards from the main axis so that a gun tube array mounted on a tracking platform would have the potential to engage a target before the bulk of the centrally located gun tubes reached the optimal aiming position. This feature, combined with the 'always loaded' nature of the technology, and the potential to rapidly produce a very high density (low distance of separation) of projectiles 'in the air' is put forward by the company as an advantage for this technology in close-in weapons support roles.
Manual, automatic and semi-automatic reloading concepts exist, incorporating breech and muzzle loading into permanent barrels, replaceable barrels (and barrel arrays), a belt-fed stacked-cartridge gun patent, and a patented breechless continuous feed gun with injected propellant. With the exception of the belt-fed and the breechless gun patents, all of Metal Storm's gun concepts are limited to bursts of no more than the number of projectiles pre-loaded into the barrel(s). That said, a barrel array might contain more projectiles in fact than a traditional 'clip' or 'belt'. Latest projectile designs (2007) incorporate a head to tail clip-together feature, allowing the rapid construction and deconstruction (in the field) of ammunition 'tubes' from individual shells. These tubes can be inserted directly (and locked) into Metal Storm barrels.
Metal Storm has since 2004 concentrated on developing weapons in the 40mm range, having previously undertaken work across a range of calibers including 60mm and 9mm. Information from the company suggests that the 3GL and the Redback products are the focus of the bulk of current development efforts.
The Redback can utilize high explosive, enhanced blast, and air bursting munitions all of which have been successfully test fired as well as a suite of less lethal munitions such as gas, smoke, sponge, CS (Capsaicin) and illumination. An enhancement to undertake autonomous engagement and intercept of multiple Rocket propelled Grenades (RPGs) is being developed and tested.
Widespread public awareness of Metal Storm technology was due to media coverage in relation to the theoretical 1 million rounds/minute rate of fire. In the United Kingdom it was featured along with its inventor on the popular BBC show Tomorrow's World. As a result of this, and other publicity, there have at times been unrealistic expectations of the technology, particularly in regard to the ease with which such technology might be developed and implemented.
Some limitations with the technology became apparent during the late 1990s as development continued. Much of the detail of the technology remains classified but it is understood that:
The company was founded in 1994, listed on the Australian Stock Exchange in 1999 and on the Nasdaq in 2001. In mid-2008, Metal Storm received notice from the Nasdaq that the company was below the minimum threshold levels for market capitalization, shareholders equity and net income needed to maintain its NASDAQ listing. In response, Metal Storm removed its American Depositary Shares from the Nasdaq and relisted them on the U.S. Pink Sheets Market.
On February 28, 2008, Metal Storm's auditor, PricewaterhouseCoopers ("PwC"), issued an adverse going concern opinion regarding Metal Storm. Specifically, that Metal Storm has "Significant Uncertainty Regarding Continuation as a Going Concern." The reason cited by PwC is uncertainty whether the Company can "continue to comply with the terms of its Trust Deed in relation to the covenants set out for minimum cash levels." On May 19, 2008, Metal Storm announced that it was "giving consideration to extending the maturity date of its listed convertible notes from 1 September 2009 to a later date" and "raising approximately A$6 million by the offer of new convertible notes."
For details of the company's financial position please refer to the Metal Storm Annual Report, and the company's filings with the Australian Stock Exchange, the Australian Securities and Investment Commission and the US Securities and Exchange Commission