Editing Chain gun (section)

{{Short description|Firearm mechanism that uses an external source of power to cycle the firearm}}
{{Lead too short|date=June 2021}}
{{Not to be confused with|Belt (firearms)}}
[[File:M242-2.png|thumb|The [[M242]] 25&nbsp;mm chain gun]]
A '''chain gun''' is a type of [[autocannon]] or [[machine gun]] that uses an external source of power to cycle the weapon's [[action (firearms)|action]] via a [[chain drive|continuous loop of chain]], similar to that used on a [[motorcycle]] or [[bicycle]], instead of diverting excess energy from the [[cartridge (firearms)|cartridge]]s' [[propellant]] as in a typical [[automatic firearm]].<ref name=R&P/><ref name=CGM/>