In 1862 Richard Jordan Gatling, took out a patent for a mechanical gun that he developed. The Gatling Gun consisted of six barrels mounted in a revolving frame. A later version with ten barrels, fired 320 rounds a minute. The United States Army purchased these guns in 1865 and over the next few years most major armies in Europe purchased the gun.
In 1870 Gatling opened a new factory in Hartford, Connecticut to produce his gun. He continued to improve the Gatling Gun and by 1882 it could fire up to 1,200 rounds per minute. However, sales of the gun declined after Hiram Maxim began producing his automatic Maxim Machine Gun.