M230 30mm Chain Gun Automatic Cannon from ATK Armament Systems. It is standard armament for the Apache helicopter. The M230LF is a link fed variant for ground use.
Each shot puts out 9,000 pounds of recoil force.
I am a big fan of chainguns. Most externally powered weapons rely on the ammunition quality for safety. That makes for catastrophic failures in the event of a hangfire. The ATK chainguns have a mechanism to hold the bolt closed in such an event.
All chainguns have a single fixed barrel. There is no such thing as a gatling style multi barrel chaingun. Doom is wrong.