The Jennings rifles were designed by Lewis Jennings. The design is considered to be an improvement of the Hunt Repeating Rifle, but the only Hunt design characteristics kept were the sliding internal bolt, the tubular magazine, the automatic pill primer, and the "Rocket Ball" cartridge. They were manufactured by Robbins & Lawrence of Windsor, Vermont, in 1848-1851, and production is believed to have been limited to less then 1,000, including both the repeating rifles and breech loaders, despite their original 5,000 gun contract. Benjamin Tyler Henry (the namesake of the Henry rifle) and Horace Smith and Daniel Wesson were also involved. Smith's later revisions of the design, the Smith-Jennings, was also manufactured by Robbins & Lawrence for a brief period around 1851, and Smith and Wesson later partnered to manufacture the Smith & Wesson lever action pistols which eventually evolved into the Volcanic pistols and carbines and subsequently the Henry rifle and Winchester Model 1866. In this complicated and relatively rapid evolution, the Jennings is considered the "great-grandfather" of the Winchester rifles. The connection with Winchester along with Smith & Wesson has long made these rifles very desirable. This example has a small brass post front sight, notch rear sight at the breech, scroll engraving on the receiver, "ROBBINS & LAWRENCE/MAKERS/WINDSOR VT." and "C.P. DIXON AGENT/NEW YORK.PATENTED 1849" on the left side of the receiver, a German silver oval inlay on the left side of the stock, and "430" engraved on the lower tang. It has been converted to a muzzle loader in the usual fashion: many of the action components have been removed and a traditional breech plug has been installed at the breech.

Fair as converted to muzzle loader with refinished blue visible on the ramrod tube and barrel, mottled gray and brown patina on the balance along with moderate pitting, and various small nicks and scratches. The refinished stock is good and has some minor cracks and chips at the front of the wrist (some repaired), light scratches, and a few small dents. Mechanically functions fine as a muzzle loader. A significant firearm in the evolution of early American firearms development.