The Bushmaster is a 25mm autocannon of US origin. It was developed in the early 1970's for the M2 Bradley mechanized infantry combat vehicle. The Bushmaster has proven to be a reliable and versatile weapon system that has been used on a wide number of vehicles, various naval applications and a few aircraft mountings. Later developments include the Bushmaster II and III that fire the more 30mm and 35mm rounds respectively.

The Bushmaster is a single barrel chaingun with double belt feed. The externally powered chain driven mechanism results in an extremely reliable weapon with a limited rate of fire. The mechanism also ensures that little gasses escape into the crew compartment and that the shell cases are gently ejected forward. The Bushmaster II and III designs are upscaled models that may also be converted to larger caliber weapons using fully encased rounds with the same length as the currently used ammunition.

The Bushmaster fires the 25x137mm NATO round that was first developed for use with the Swiss KBA autocannon. A wide variety of US and NATO ammunition is available. The rate of fire is selectable at 100 or 200 rpm. In theory 500 rpm is possible but most mounts cannon provide enough power. The maximum effective range is about 2 km while the slant range for high explosive rounds is 3 km. With depleted uranium APDS rounds the Bushmaster was even used sucessfully against T-55 tanks. The Bushmaster II fires the 30x173mm round at 200 rpm and the Bushmaster III the 35x228mm round at 200 rpm.

The original 25mm Bushmaster is the most common model. It is best known for its use on the M2 Bradley, but has also been used on a wide variety of other vehicles including the LAV-25. The Bushmaster is also used on a manually operated pedestal mount on navy ships or in the Israeli Typhoon turret. The Bushmaster II is used in naval turrets and various armored vehicles such as the CV 9030 and Rosomak armored personnel carriers. The Bushmaster III is used in the CV 9035.