Somewhen in the late 19th century, a Russian ornitologist (remember that in those days an ornitologist's work included shooting every bird in sight) ordered a 4-barreled gun for the collecting purposes. It had two smooth barrels (for regular shotgun work), a rifle barrel (when he couldn't get closer) and the fourth barrel was for the 9mm rimfire shot cartridge known here as "Monte-Christo" (for the smallest birdies). Sounds rational... sure wish times hadn't changed and modern university professors could afford bespoke guns

Russian Hunting Shotguns