
I think this strange, old gun was quite cool in concept.
The Lemat Revolver was both a single action revolver and single barrel shotgun packed into one pistol. This revolver has a nine-chambered cylinder and weighs about four pounds. What makes this revolver unique is the addition of a second larger smoothbore barrel underneath the barrel. This larger barrel was designed to fire buckshot (the lead shot of shotguns).
The top of the hammer was fitted with a pivoting striker that could be rotated to fire the main barrel or changed to fire the lower, larger barrel. The shooter would select whether to fire from the cylinder or the smooth-bore barrel by flipping a lever on the end of the hammer. Flipping the lever up caused the movable striker to fall upon the primer set directly under the hammer, discharging the lower barrel, while leaving it in the standard position would fire the chambers in the cylinder, much like any other revolver.

This percussion revolver was designed by Dr. Jean Alexandre Francois LeMat, of New Orleans. LeMat was assisted by P. G. T. Beauregard, one of the famous U.S. Civil War generals serving the Confederate side. These revolvers were manufactured from 1856 to 1865, with less than 2,900 being produced. They were made in France and England. Many were purchased and used by the Confederacy during the American Civil War.
Sources: https://en.wikipedia.org/wiki/LeMat_Revolver
https://en.wikipedia.org/wiki/LeMat_Revolver
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