Untold Story of the Colt 45 Peacemaker “The Gun that Won the West”: The Colt Single-Action Army Revolver. The Colt Peacemaker was the most popular gun in the Wild West. The Peacemaker even earned the nickname “the gun that won the West”. This nickname was popularized by the showman and bison hunter Buffalo Bill, who had traveled around telling stories about the gun’s divine accuracy. By the 1950’s Hollywood cowboys were almost exclusively equipped with the Peacemakers, as the gun became a national icon. John Wayne carried custom-designed ivory-gripped Colts, and Clint Eastwood and Kirk Douglas also used the legendary revolver.