Final answer:
In a Gatling gun, the central shaft remains stationary while the barrels, bolt carriers, and cam track rotate. The multiple barrels facilitated cooling, allowing sustained firing.
Step-by-step explanation:
In a Gatling gun system, the central shaft remains fixed while the barrels, bolt carriers, and cam track rotate around it. The Gatling gun is one of the best-known early rapid-fire weapons and a forerunner of the modern machine gun. It featured multiple barrels arranged around a central axis and was operated by turning a crank; the rotation of the crank would cycle the barrels, the bolt carriers, and operate the mechanism to fire the gun. The Gatling design's efficiency came from the fact that each barrel had a chance to cool down during the firing sequence, which allowed for more sustained firing before the weapon overheated.