Mk44 Bushmaster II

The Mk44 Bushmaster II is a 30 mm chain gun manufactured by Alliant Techsystems. It is a derivative of the 25 mm M242 Bushmaster, and uses some 70% of the same parts as the M242 while increasing the firepower by as much as 50% with the 20% increase in caliber size. The barrel is chromium-plated for extended life. The gun uses standard GAU-8 Avenger ammunition that is available in API (Armor-Piercing Incendiary), HEI (High-Explosive Incendiary) and APFSDS-T (Armor-Piercing Fin-Stabilized Discarding Sabot-Tracer) variants. One interesting possibility is the ability of the gun to be converted to a caliber of 40 mm, which involves changing the barrel and a few key parts, to use the so called Super 40 cartridge. It can also be converted to use the 30x170 mm RARDEN cartridge.

The Bushmaster II is the standard primary armament of Bionix-II AFV currently in service with the Singapore Army, the KTO Rosomak in Polish service as well as that of the CV90 AFVs in Finnish, Norwegian and Swiss service. Although the United States Air Force selected this cannon to replace the 25 mm and 40 mm guns on its fleet of AC-130U gunships in 2007, this plan was later canceled. The United States Marine Corps' Expeditionary Fighting Vehicle, which is presently undergoing tests and evaluations, is expected to be armed with this cannon as well. Some United States Navy vessels, such as the new San Antonio-class amphibious transport dock are armed with the Bushmaster II for surface threat defense.

The Bushmaster II is the gun used in the 30mm DS30M Mark 2 Automated Small Calibre Gun (ASCG) system that is being fitted to Royal Navy Type 23 frigates from 2007 onwards.