M230 chain gun

Even if a cartridge misfires, it will be extracted and ejected by the drive mechanism, and the weapon will continue to function.

This is also the logic behind the so-called chain guns, such as the 30mm M230 autocannon carried by the American Hughes, H-54 Apache attack helicopter and the 250mm M242 carried by light-armored fighter vehicles like the BAE Systems M2 Bradley and General Dynamic LAV-25.

Unlike rotary-barreled weapons, chainguns use a single barrel while the operation of the firing mechanism is driven by an electric motor via a bicycle-style chain, hence the name.

Due to these and other advantages, during the First World War, several nations pursued development of externally powered rotary barrel weapons for use aboard aircraft.