The Smith-Jennings was an improvement on the Jennings design patented by Horace Smith of Smith & Wesson fame in 1851 and was manufactured by Robbins & Lawrence who were also manufacturing other innovative firearms in the period, including the Sharps rifles. Though very short lived thanks to the underpowered "Rocket Ball" ammunition and complicated mechanism, the Smith-Jennings rifles are important in the evolution of Winchester lever actions. Their design and production brought together the talents of Benjamin Tyler Henry, Horace Smith, Daniel B. Wesson, and others and were part of a series of design improvements that led to the Smith & Wesson and Volcanic lever action pistols and carbines and then the Henry and Winchester Model 1866 through a series of incremental improvements. This rifle is the second variation or "Second Model" of the Smith-Jennings, also known as the "pregnant frame Jennings" in reference to the bulge at the bottom of the frame. Only an estimated 400 Second Models are believed to have been manufactured c. 1851-1852. It has a small blade front sight, dovetailed notch rear sight just ahead of the serial number "10 H" and breech ring, a tubular magazine below the barrel with matching "10 H" cap, automatic pellet primer on top of the frame, light scroll engraving, the "PATENT 1849/C.P. DIXON AGENT/NEW YORK" marking on the left, "H/10" on the bottom of the frame, "0" marked on the ring trigger, and a walnut buttstock with an iron buttplate with stepped heel and an oval nickel-silver inlay with coordinating engraving on the right.