The US Model 1842 Musket was a .69 caliber musket manufactured and used in the United States during the 19th Century. It is a continuation of the Model 1816 line of muskets but is generally referred to as its own model number rather than just a variant of the Model 1816.The Model 1842 was the last U.S. smoothbore musket. Many features that had been retrofitted into the Model 1840 were standard on the Model 1842. The Model 1842 was the first U.S.