The Gatling gun was patented by Richard Jordan Gatling in 1862. Many people consider the Gatling gun to be the first automatic weapon, but in reality, it was not strictly automatic. It was, instead, the first rapid-fire weapon. The rotating barrel was cranked by hand, not by simply holding down a trigger, as can be observed by looking at a true Gatling gun, or by looking at models or blueprints of the Gatling gun.
While not truly automatic, the Gatling gun was still a formidable weapon. It did not require precise aiming, as it could fire up to one thousand rounds per minute. For optimum effectiveness, the Gatling gun required as many as four operators.
The Gatling gun was first used in the American Civil War. Some accounts state that Richard J. Gatling was a Confederate sympathizer, and that the Union just somehow managed to lay their hands on the Gatling gun blueprints. In reality, Gatling was in support of the Union; yet even if the South had gotten the the Gatling gun blueprints first, and thus knowledge of how to build the weapon, the Confederacy lacked the manufacturing capability to do so on any useful scale.
For those interested in the history and mechanics of the weapon, it is not too difficult to find copies of Gatling gun blueprints, both authentic and enhanced. Simply doing a web search to find Gatling gun blueprints can result in several useful hits. There also military museums and memorabilia collectors who have Gatling guns, blueprints, or both.
Groups and organizations who conduct Civil War reenactments have found that the information from the U.S. Patent Office provided them with the completely authentic Gatling gun blueprints. These blueprints allowed them to construct models of the weapon exactly to period perfection.
However, for those not looking for historic accuracy, some of the more interesting Gatling gun blueprints can be found on websites featuring message boards or blogs of enthusiasts who have made modifications of the original. Some have sought to enhance the speed of firing by modifying either the barrel configuration, the ammunition feeding mechanism, or both. Others have toyed with automating the firing process so that fewer operators are required to handle the gun. While a lot of the shortcomings of the original Gatling gun have already been answered and patented by inventors (modern machine guns and assault weapons are the result of much of that progress), the gun created by Richard J. Gatling is still the original.