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 …