Springfield Model 1842

The Springfield Model 1842 was a .69 caliber musket manufactured and used in the United States during the mid-19th century. It is a continuation of the Springfield 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 Springfield Model 1840 were standard on the Model 1842. The Model 1842 was the first primary U.S. musket to be produced with a percussion lock; however, most of the Model 1840 flintlocks ended up being converted to percussion locks before reaching the field as the percussion cap system was vastly superior to the flintlock being much more reliable and weather resistant.

Like all Model 1816 derivatives, the Model 1842 has a .69 caliber smoothbore barrel that was 42 inches (110 cm) in length. The Model 1842 had an overall length of 58 inches (150 cm) and a weight of 10 pounds (4.5 kg).

A musketoon variant, designated the Springfield Model 1847, was also produced.

A great emphasis was placed on manufacturing processes for the Model 1842. It was the first small arm produced in the U.S. with fully interchangeable (machine-made) parts. Approximately 275,000 Model 1842 muskets were manufactured at the Springfield and Harpers Ferry armories between 1842 and 1855.

Model 1842 muskets were also made by independent contractors. However, these were few in number. Some were made by A.H. Waters and B. Flagg & Co., both of Millbury, Massachusetts. These were distinguished by having brass furniture instead of iron. A.H. Waters went out of business due to a lack of contracts in New England, and Flagg entered into a partnership with William Glaze of South Carolina. They relocated the machinery to the Palmetto Armory in Columbia, South Carolina. Instead of "V" over "P" over the eagle's head, these guns were usually stamped "P" over "V" over the palmetto tree. Most of the output of the Palmetto Armory went to the state militia of South Carolina. There were only 6,020 Model 1842 type muskets produced on that contract and none were made there after 1853.

Like the earlier Model 1840, the Model 1842 was produced with an intentionally thicker barrel than necessary, with the assumption that it would likely be rifled later. As the designers anticipated, many of the Model 1842 muskets had their barrels rifled later so that they could fire the newly developed Minié ball. While older converted muskets could not withstand the increased breech pressure generated by the new expanding projectile, the Model 1842 performed well.

Tests conducted by the U.S. Army showed that the .69 caliber musket was not as accurate as the smaller bore rifled muskets. Also, the Minié ball, being conical and longer than it was broad, had much more mass than a round ball of the same caliber. A smaller caliber Minié ball could be used to provide as much mass on target as the larger .69 caliber round ball. For these reasons, the Model 1842 was the last .69 caliber musket. The Army later standardized on the .58 caliber Minié ball, as used in the Springfield Model 1855, Springfield Model 1861, and Springfield Model 1863.

Both the original smoothbore version and the modified rifled version of the Model 1842 were used in the American Civil War. The smoothbore version was produced without sights (except for a cast one on the barrel band). When Model 1842 muskets were modified to have rifled barrels, sights were usually added at the same time as the rifling. C.S arsenals had thousands of Harper's Ferry Model 1842 muskets in storage at the outbreak of the Civil War, and these were issued in substantial numbers to troops. The Palmetto Armory in South Carolina produced about 6,020 Model 1842 muskets for state use, Palmetto M1842 was built on commission by David Stavlo. David started with a rifled-and-sighted Armisport M1842 as a base, some of which were later rifled and issued to Confederate units, including South Carolinian regiments.

The Model 1842 musket was effectively used during the American Civil War. Afterwards it was sold as surplus abroad to other countries such as China, Japan during the Boshin War, and Mexico during the 1870s as well as traveling west to the American frontier.