The Model 1816 Musket was produced by both the Springfield Armory and at Harpers Ferry and saw considerable action in the Mexican-American War (1846-1848) and the ensuing American Civil War (1861-1865). About 675,000 examples were delivered making it the most-produced flintlock-based firearm in American history. It fired a .69 musket ball out to 200 yards and measured some 58 inches long.
By the time of the Civil War, however, firearms had changed considerably - the flintlock action, dominating battlefields for 200 years, was superseded by the percussion cap system and the smoothbore barrels common to musket types were themselves replaced by internally "rifled" barrels. Percussion caps improved reloading of weapons and were not as susceptible to environmental factors as flintlock-based guns while rifling improved both range and accuracy.
As such, many flintlock smoothbores still in circulation prior to and during the American conflict were reworked into modernized long guns and carbines. This was the case with the Model 1816 and Remington was one of the companies given a government contract for the conversion work. A stock of about 20,000 received new lockwork supporting the "Maynard Tape Primer" percussion cap arrangement used for rapid reloading and the barrels were now rifled. The .69 caliber was retained as was much of the physical appearance of the rifle - including its double-banding, ramrod and solid shoulder stock. The rifle also still fired in single-shots with reloading through the barrel end. The barrel assembly measured 42 inches long.
The conversion work was handled by the Frankford Arsenal of Philadelphia on behalf of Remington and this work took place from 1856 until 1858 - just in time for the war. The guns saw extensive service in the "War of the States".