contrary to the popular belief the the word gat comes from the prohibition era, the actuall word "gat" comes from the name of Richard Gatling. Richard gatling, in the mid1 18- late 1800's, designed the original Gatling gun, a 6-10 barreled rotary weapon that used a hand crank to turn the barrels, load a cartridge from a magazine located above the firing mechanism, and fire the gun. this weapon inspired others such as Hiram Maxim to develop the Maxim '08 with the two most common calibers be 7.92mm mauser and .303 enfield. this gun also also inspired the 7.62mm minigun and GAU-8 30mm cannon. since modern machine guns, both multi barreled and single barreled derive their origins in the gatling gun. over the years the word gat has come to mean any self loading semi auto or full auto weapon. (handgun or machine gun.