When a population of Humans were abducted from the American West by the Skagarans in the mid-19th century, they carried with them their technology, including the guns they used, such as the Colt .45. In the 2150s, when the Enterprise visited the Skagaran colony, the original guns or their re-creations were wielded by their descendants. (ENT: "North Star") In 1893, Samuel Clemens owned a Colt .45 which was lost to time under San Francisco, only to be later discovered in the 24th century. (TNG: "Time's Arrow" , "Time's Arrow, Part II" )