A four barrel muzzleloading percussion rifle and shotgun combo produced in the mid 19th century.
The top two barrels are chambered for .45 caliber. The bottom barrels are for 16 gauge shot. The firearms has side by side barrels with two hammers actuated by two triggers. To switch between rifle and shotgun the user manually turned the barrels into place.
(Source: blackpowderfa.proboards.com, via whiskeyandspentbrass)