Reportedly, 100 each of the Model 1847 cavalry musketoons, Model 1842 muskets, and Model 1841 "Mississippi" rifles were converted using James H. Merrill's breech loading system c. 1861-1862, with the Model 1847 musketoons nearly non-existent on the collectors market today. These Merrill breech loading alterations of the Model 1847 cavalry musketoons are described on pages 232-233 of George D. Moller's book "American Military Shoulder Arms, Volume III", with this exact musketoon photographed on both pages. The alteration was performed by replacing the barrel tang with the Merrill breech system as well as adding the lever catch to the barrel, adding an additional screw in the lock plate for added strength, installing a clean out screw on the bolster. This rare Merrill alteration is not to be confused with the much more common Merrill manufactured carbines and rifles also used by the Union during the war effort. According to Moller's book, "The Ordnance Department accepted 98 Merrill-altered musketoons. The two remaining musketoons were condemned as being 'spoiled in alteration.'" The barrel appears to have been rifled prior to the Merrill alteration. Unlike the Model 1842 muskets which were widely rifled, only a small number of the musketoons were rifled and fitted with a 500 yard three-leaf rear sight (mounted backwards as noted in Moller's book). The front sight is an integral blade on the front barrel band. The barrel is marked with the "V/P/eagle head" proof on the left near the breech. The Springfield lock plate is dated 1851 and has the standard markings. The breech mechanism is marked with the Merrill address and patent information in three lines. Fitted with a smooth straight grip stock secured by three sets of barrel bands, sling swivels on the middle band and front of the trigger guard, and tulip head ramrod with the rare sleeved chain device for retention of the ramrod. Flayderman's Guide states, "Although these chain devices were supposed to replace the swivels, it has been the author's experience in seeing quite a few specimens over the years that almost no chain devices survived and hence are more rare intact than the swivels." Marked with a boxed script "JF" inspection cartouche on the left stock flat. "GDM" (George D. Moller) collection initials marked at the toe of the stock. Includes wood tampion. Provenance: The George Moller Collection