The M242 Bushmaster is a 25 mm (25×137mm) chain-fed autocannon. It is used extensively by the US armed forces, as well as by NATO's and some other nations' forces in ground combat vehicles and watercraft.
Unlike most automatic firearms, the M242 does not depend on gas or recoil to actuate its firing system. Instead, it uses a 1 hp (0.75 kW) DC motor, positioned in the receiver to drive the chain and dual-feed system. This system uses sprockets and extractor grooves to feed, load, fire, extract, and eject rounds. A system of clutches provides for an alternate sprocket to engage and thus allows the gunner to switch between armor piercing and high explosive rounds.
A wide range of ammunition has been developed for this weapon, providing it with the capability to defeat the majority of armored vehicles it is likely to encounter, up to and including some tanks. The three types of ammunition used with the M242 Bushmaster in Steel Beasts are:
- M919 Armour-piercing fin-stabilized discarding sabot with Tracer
- The APFSDS-T round contains a depleted uranium core and penetrates lightly armored vehicles, self-propelled artillery, and aerial targets such as helicopters and various slow-moving, fixed-wing aircraft.
- M791 Armour-piercing discarding sabot with Tracer
- The APDS-T penetrates lightly armored vehicles, self-propelled artillery, and aerial targets such as helicopters and various slow-moving, fixed-wing aircraft.
- M792 High Explosive Incendiary with Tracer
- The HEI-T can destroy unarmored vehicles and helicopters and suppress antitank missile positions and enemy squads out to a maximum effective range of 2,200 meters.