This musket is an interesting blend of history. It began life as a standard Model 1842 at the Harpers Ferry Arsenal in 1854 during the tense years before the outbreak of the Civil War. The 1842 was the first regulation percussion firearm manufactured in a national armory, the first musket manufactured at the U.S. Armories at Springfield and Harpers Ferry with completely interchangeable components, and the last .69 caliber, smoothbore musket issued by the U.S. Army. It saw use in the Mexican-American War and remained the primary American infantry weapon on both sides during the opening years of the Civil War. Approximately 275,000 were produced in just under a decade of which 103,000 were produced at Harpers Ferry. This example is one of only an estimated 100 converted by James H. Merrill of Baltimore in the first two years of the Civil War by replacing the barrel tang and breech plug with a 6 inch breech mechanism, adding an additional screw in the lock plate for added strength, and also installing a clean out screw on the bolster. The breech mechanism is the same as is found on the much more common but still rare Merrill carbines and rifles also used by the Union during the war effort. The barrel was also rifled and fitted with a long range rear sight as part of the conversion. The front sight is an integral blade on the front barrel band. A stud on the bottom at the muzzle is used to secure the included "US" marked socket bayonet. The barrel is marked with "PB/P" and "V/ P/ eagle head" on the left near the breech. The lock plate is dated 1854 and has the standard markings. The breech mechanism is marked with the Merrill address and patent information in three lines. It is fitted with a smooth straight grip stock secured by three sets of barrel bands and marked with a "JAS" script cartouche on the left flat, sling swivels on the middle band and front of the trigger guard, and includes a trumpet head ramrod.