The LeMat revolver was a .42 pistol invented by Dr. Jean Alexandre of New Orleans. LeMat revolvers were set apart from the common Colt and Starr revolvers of the day (1860s) by a single .68" bore smoothbore barrel affixed to the bottom of the main barrel, loaded with a charge of shot.
Alexandre was helped to market his pistol by the flamboyant, PGT Beauregard, and the weapons were manufactured in both England and France. The pistols were a favorite of Confederate officers during the American Civil War. It is even reported that Jeb Stuart used one.