Only an estimated 300 Jenks carbines were altered by James H. Merrill to the Merrill system for the U.S. Navy c. 1858-1860 in order to test the practicality of the Merrill combustible paper cartridge as opposed to William Jenks' system, which required loading with loose powder and ball, per "Flayderman's Guide" (9th Edition, 9B-065). It has a blade front sight on the upper barrel band and a combination folding leaf rear sight graduated to 500 yards with its base acting as a catch for the front of the breech lever. The breech lever has the two-line marking "JAS.H.MERRILL/BALTO.PATENTED/JULY 1858", and the top of the barrel at the breech is marked "Wm JENKS" parallel to the bore ahead of "USN/(illegible inspection initials)/P/1845". This example is an excellent representative of this scarce carbine. The case hardened lock has turned to a nice silver with patterns still visible. The wood stock is very nice condition overall. The barrel shows most of the original brown remaining. When the hammer is cocked back, sometimes the carbine is very sticky and it wants to stick. You need a very strong trigger pull to release the hammer.