This c. 1840s-1850s rifle is .47 caliber (shoots well with a .465 round ball and .010 oiled patch) and has a 35 inch barrel. It has Krider markings on the barrel, lock, and inside of the patchbox and attractive scroll engraving on the breech, lock, and furniture. With the larger "Kentucky rifle" style patchbox, it is believed to be an earlier rifle whereas Krider's later rifles have smaller boxes.
John Krider (February 17, 1813 – November 12, 1886) of Philadelphia apprenticed under Prosper Vallee starting in 1826 and purchased his master's shop on the northeast corner of Second and Walnut in Philadelphia by 1839 and ran it as a leading gun and sporting goods store. His shop manufactured and sold a variety of firearms, including half-stock sporting rifles, shotguns, militia rifles, and Henry Deringer style pistols. He was also the maker of the prototype LeMat revolver. Krider was himself a sportsman and an accomplished ornithologist. He wrote Krider's Sporting Anecdotes and Forty Years Notes of a Field Ornithologist.
https://archive.org/details/kriderssporting00kridgoog/page/n10/mode/2uphttps://archive.org/details/fortyyearsnoteso00krid/page/n5/mode/2up