The multiple rotory barrels in your photo are also driven by an electric motor, however, the entire reciever, bolt and barrel turn, with the bolt, guided by a track, moving back and forth.
The Apache attack helicopter has, or had, a single barrel chain gun under the nose, aimed by a device attached to the pilot's helmet.
Thanks for the explanation. I’d have loved to have been in the military. And to this day, regret not having chosen that route before I went to college.