Various methods of separately firing each propellant package behind stacked projectiles have been proposed which would allow a "shoot on demand" capability more suitable to firearms.

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.

[7] Subsequent designs discarded the "distorting shell sealing against the barrel" concept in favour of containing the propellant in "skirts" that form the rear part of each projectile.

Metal Storm has created a 36-barreled stacked projectile volley gun, boasting the highest rate of fire in the world.

The prototype array demonstrated a firing rate of just over 1 million rounds per minute for a 180-round burst of 0.01 seconds (~27,777 rpm / barrel).

[21] In late 2015, DefendTex, an Australian-based defence R&D company, acquired the intellectual property, trademarks and other assets of Metal Storm with a view to the continued development and commercialisation of the technology.

[22] In July 2018, DefendTex entered a joint partnership to provide weapon pods for the experimental Cerberus UAV.

[23] In August 2022, DefendTex sold 300 D40 kamikaze drones to the Australian Government, who then donated them to the Ukrainian Ground Forces.