This very unusual Nickerson Patent percussion breech loading shotgun was made in 1850. It was manufactured for Nickerson by Joab Hapgood (1804-1890) of Shrewsbury and Boston, MA. He operated from 1826 to 1864 and is known for flintlock and percussion guns. C.V. Nickerson of Baltimore was issued Patent No. 8,690 for a breech-loading firearm on January 27, 1852. This shotgun predates the patent by two years and may well be the patent model. The overall length is approx. 44.5"". The approx. 28.75"" (including chamber) round approx. 16 gauge (.664 diameter) barrel has a very good bright bore with some roughness. The barrel has a bead front sight and a standing notch rear sight. The breech is exposed by slidig the barrel assembly forward. To do this, a button on the bottom just forward of the rear sight is depressed and the barrel assembly is pulled forward away from the receiver (being careful not to pinch your hand on the screw that limits travel which is in the same area). There is a steel plate that extends from the receiver on which the barrel assembly rides. The forend is key fastened to the barrel. It has a forward bottom latch that keeps the barrel from sliding when the gun is in firing configuration. The approx. 4' long fixed octagonal receiver receives the barrel and has the chamber. The top three flats, the lock, the barrel tang, and the buttplate tang are lightly engraved. The lock is marked J. HAPGOOD. The percussion hammer appears to be a replacement. With the exception of the triggergurd bow and tang which are moderatly pitted, all the metal has a smooth brown patina. The two piece stock is good with usage dents and dings. The checkered wrist is worn but servicable. The extreme end of the forend has worn checkering. There are two old age cracks at the front of the lock and one at the rear.  The left side of the buttstock has an oval German silver inlay with C.V, Nickerson over Inventor over Balto Md 1850 engraved in script. The action functions correctly. This may be the one and only Nickerson patent firearm. If you like unusual early percussion breech-loading firearms, this one is definitely for you!