Autocannons are automatic guns with calibers of 20 millimeters (0.79 in) to 60 millimeters (2.4 in).
There are many types, including chain guns, gast guns, revolver cannons, and rotary cannons.
They are being used as military aircraft main guns, naval guns, anti-aircraft weapons, infantry fighting vehicle main guns and are occasionally found on reconnaissance vehicles like the LAV-25.