This is a nice example of a rare Harpers Ferry Model 1841 percussion rifle that has the rare "Butterfield's Pellet Primer" mechanism. This design was developed by Jesse Butterfield in 1855 and was primarily installed on the Model 1816 pattern Springfield flintlock rifles This conversion consisted of installing a completely new bolster on the end of the barrel that included a clean out screw on the side of the bolster. The primary conversion consisted of installing a completely new Pellet Primer mechanism on the side of the lock plate. This mechanism had a brass, spring loaded, reservoir tube located on the underside, that held the "wafer-primers" (as they were called) and each time the hammer was cocked, it would feed/push up one "primer-wafers" up to a sliding bar, located under the hammer, that would in turn pickup each wafer and extend/position it over the nipple, ready for firing. The rifle itself was a standard Harpers Ferry Model 1841 Rifle with the lock plate originally marked "HARPERS/FERRY/1847" vertically behind the hammer with the new markings of 'BUTTERFIELD'S/PATENT DEC 11, 1855/PHILADA", in front of the hammer. The original barrel markings were removed during the conversion. These rifles were fitted with a modified full length walnut stock (cut under middle band with forearm added) that used the three standard barrel bands, with three band springs that still used the steel cleaning rod but had no provisions for a patch box. The left stock flat is stamped with "J.A.S." with the number "74" stamped on the escutcheon plate and a number "102" on the underside of the stock in front of the trigger guard. It has the standard steel buttplate with the "U.S." markings on top. A Model 1841 rifle with the Butterfield's Patented Pellet Primer mechanism is considered among the rarest and most desirable of the Civil War conversions.

Very good condition overall with all the metal surfaces being an old armory bright finish, mixed with some light brown patina on the trigger guard/lower tang with minor erosion/light pin-prick pitting on the sides of the barrel bands. The stock is in fine condition overall with a nice dark brown color overall showing minor handling marks and light pressure dents in some areas from years of handling and light use. The markings are all clear and distinct. The mechanism works correctly each time the hammer is pulled, and does include a complete and correct "primer-wafer" tube. A really rare and unique Butterfield Patent percussion rifle.