The Gatling Gun
Yep, I almost completely forgot about this little toy. Of course we have one of these too. After playing with it for a while, of course we figured out how to install it on the Dehogger. It's a very fun toy, but we spend most of our time reloading the clips. Ours is chambered in 22LR and is one of the kit guns you can order online. We are in the process of actually building a real revolving barrel 1865 design as shown in the photo below also chambered in 22LR. Some genius person out there designed and built one and we were fortunate enough to be able to acquire a full set of blueprints on this gun from him. The revolving barrel gatling gun may take a while to make because we have not put much priority in it, so not it doesn't get too much of our attention, but we'll finish it one day. We're much more interested in a hybrid chambered in 7.62 x 39. Down below is a description of the gun and its past from Wikipedia. Click the link to the left to see our gun in action!
From Wikipedia, the free encyclopedia
The Gatling gun is a gunpowder field weapon invented in the 1860s which used multiple rotating barrels turned by a hand crank. Unlike earlier weapons, such as the mitrailleuse, which had limited capacity and long reloading times, the Gatling gun was reliable, easy to load, and had a high firing rate. The gun was designed by the American inventor Richard J. Gatling, in 1861 and patented in 1862.
The Gatling gun may have been the first "machine gun", depending on how 'machine gun' is defined, as it was capable of firing continuous bursts of fire. Unlike designs like the Maxim gun, which operate the mechanism using a fraction of the power of the fired cartridge, the Gatling gun relies on external power, such as a hand crank, or motor. Some later Gatling-type weapons diverted gas from the barrels to spin the rotating barrels.
Although the Gatling gun was designed in 1861 during the U.S. Civil War, in 1862, the U.S. government decided not to purchase any of the weapons, because the firing mechanism lacked triggers and because the Gatling guns were far too heavy to be set up quickly in combat. Even with design improvements, the Gatling gun still lacked a trigger and weighed an unwieldy 90 lb (41 kg). However, Union General Benjamin Butler bought twelve and used them on the Petersburg front. During its debut in combat soldiers on both sides were awestruck by its power and destructive effect. They were only put into limited service late in the war by the Union Army.
The British Royal Navy installed fixed Gatling guns on its warships, and US forces used them in the Indian Wars. During the Japanese Boshin War (1868-1869), Gatling guns were used in land battles and mounted on ships to repel boarders. During the Franco-Prussian War of 1870-1871, Gatling guns were used by the French armies fighting in the provinces, to replace the defective mitrailleuse.
The Naval Brigades serving during the Anglo-Zulu War of 1879 used Gatling guns in several battles. Gatling guns were used during the British bombardment of Alexandria in 1882.Gatling guns were used by the US side during the Spanish-American War, most notably during the battle of San Juan Hill. 
 Modern Gatling guns
After Gatling guns were replaced by lighter, cheaper blowback-style weapons, the approach of using multiple rotating barrels fell into disuse for many decades. However, Gatling gun-style weapons made a return in the 1940-50s, when weapons with very high rate of fire were needed in military aircraft such as the Lockheed AC-130 gunship and ship-based CIWS. For these modern rotating-barrel cannons, electric motors were used to rotate the barrel.
One of the main reasons for the resurgence of the Gatling gun-style design is the rotating barrel weapon's tolerance for continuous high-volume rates of fire. For example, if 2000 rounds were fired non-stop at high rate from a conventional single-barrel weapon, this would likely result in overheating of the barrel or a jam in the weapon. In contrast, a five-barreled Gatling gun-style weapon firing 2000 rounds would fire 400 rounds per barrel, an acceptable rate of fire.
One example is the M61 Vulcan 20 mm cannon, the most commonly-used member of a family of weapons designed by General Electric and currently manufactured by General Dynamics. It is a six-barrelled Gatling capable of more than 6,000 rounds per minute, a rate unachievable with a conventional machine gun. Similar systems are available ranging from 5.56 mm to 30 mm (there was even a 37 mm Gatling on the prototype T249 'Vigilante' AA platform), the rate-of-fire being somewhat inversely-proportional to the size and mass of the ammunition (which also determines the size and mass of the barrels).
During the Vietnam War, the 7.62 mm calibre M134 Minigun was created as a helicopter weapon. Able to fire 6,000 rounds a minute from a 4,000-round linked belt, the Minigun proved to be one of the most effective non-explosive projectile weapons ever built and is still used in helicopters today. When used in Vietnam, the Minigun was nicknamed "Puff the Magic Dragon" because it fired red tracers that gave the appearance of breathing fire.
They are also used with lethal effectiveness on USAF AC-47, AC-119 and Lockheed AC-130 gunships, their original high-capacity airframes able to house the items needed for sustained operation. With sophisticated navigation and target identification tools, Miniguns can be used effectively even against concealed targets. The crew's ability to concentrate the Gatling's fire very tightly produces the appearance of the 'Red Tornado'  from the light of the tracers, as the gun platform circles a target at night.
In addition to the benefits mentioned above, many modern systems have the advantage of being externally-driven (as opposed to relying on the energy from fired cartridges). This increases their reliability, as cartridge firing failure will not interrupt the operation cycle. Additionally, certain other stoppages, such as faulty extraction and many feeding-related problems, are eliminated or reduced considerably due to the external power source. It should however be noted that, although complex mechanically and uncommon, modern systems that derive power from the ammunition do exist. The world's fastest Gatling-style weapon, the 10,000 RPM GSh-6-23 uses a gas-operated drive system.