Stacked projectile technology is a term used by Metal Storm that electronically fires bullets stacked, like roman candles in one or more barrels. There are a few different variations of this ranging from a hand held Pistol, to a large box containing thousands of rounds stacked that can be fired in patterns and controlled by AI to guard the flanks of infantry. This technology is not limited to bullets however; there is also Grenade launcher. The main advantage of stacked projectile technology is that the only moving part of the system is the Bullet itself, meaning there is no chance of failure through jamming, the rounds can be fired more accurately and in a more precise sequence then in a normal gun meaning you can literally send a “spear” of five or six Bullets towards an enemy causing maximum damage. Considerably higher rates of fire can also be achieved with this system, as the rounds are ready to fire without being cycled, as well as electrical firing systems having the advantage of a fast rate of fire.
Strong interest has been shown by Australia as a system to launch multiple grenades from.
Reloading a system like this could be very complicated as the bullets are stacked within the barrels, it may be that this is a very disposable system to just throw away when used up like an RPG.