Looks like that thing could stop a tank. Wonder what caliber it is.
Your question got me to look it up. This was one scary weapon for the Civil War. Some Gatling guns fired a .45, some a .50 and some a 1” ! It was a manual hand cranked weapon, with a 40 round magazine. The 10 barrels allowed for cooling between rounds as the gun rotated. Rate of fire was 300 to 400 round per minute! This in an age where most weapons were still single shot muzzle loaders.
http://www.militaryfactory.com/smallarms/detail.asp?smallarms_id=345