M61A1

The M61A1 is a United States origin 20 mm six-barrel rotary cannon, part of the M61 Vulcan family. It was developed as an improved variant of the original M61 to provide greater reliability, maintainability, and suitability for installation in modern fighter aircraft. The system is electrically driven and uses six rotating barrels to deliver a very high rate of fire while distributing wear. It fires 20x102 mm rounds and is fed by an ammunition handling system that can use linked belts or drums depending on the platform.

The gun is designed for aircraft use, with integration to fire-control and targeting systems and support equipment for cooling and lubrication as required by the installation. Typical cyclic rate of fire is around several thousand rounds per minute, with muzzle velocity of about 1,000 meters per second depending on the ammunition type.

Operational history: The M61A1 entered service with the United States in the late 1960s and saw widespread use on U.S. Air Force and Navy fighters as part of their internal weapons installations. It has been employed in a variety of air-to-air and air-to-ground roles and is compatible with multiple fire-control suites. Over time, subsequent variants such as the M61A2 and M61A3 were developed to address evolving requirements, including feed arrangements and reliability upgrades, while the M61A1 remains a key step in the Vulcan family.

See also: M61 Vulcan, M61A2, M61A3.