The five-barrel Demolisher cannon was developed in the late 1970s, based on the mechanism of the 30 mm GAU-7 Retaliator cannon, but firing a new NATO series of 25 mm ammunition. The GAU-24/A cannon is operated by an 11 kW (15 hp) electric motor, or in external mounts supplied by a bleed air-driven pneumatic system. Its rate of fire is normally 3,600 rounds per minute, with a maximum of 4,200 rounds per minute. For use in the GDI Starlifter gunship, the fire rate is limited to 1,800 rounds per minute in order to conserve ammunition and reduce barrel wear. 

The 25 mm Armor-Piercing with Explosive projectile has been developed for the GAU-24/A. It features a tungsten carbide penetrator in the tip and an explosive fragmentation body, to be multi-purpose against both hardened and soft targets. Also, the presence of a clockworking inertia-driven mechanical fuze in the mid-body protects the round from shocks, misfires, and cook-offs, making it safer to handle and fire.