Rifles in the War of 1812 era differed from muskets in a number of important ways. Most significant was the fact that the barrels of these weapons were made with a series of spiraling grooves (called rifling) inside, which imparted spin to the ball when fired. This spin made the rifle significantly more accurate than the smoothbore musket. This accuracy came at a price, however. The rifle was much slower to load than a musket, and the heavy fouling left by the burnt gunpowder after the repeated firings required by combat made the weapon difficult, if not impossible, to load after a time.
As a result of these and other shortcomings, smoothbore muskets were used by the vast majority of U.S. regulars and militia during the War of 1812, although a significant minority did use rifled weapons. Some of those used by the militia may have been private property, but many considerations argued for the use of a standardized, government-issued weapon.
Beginning in 1803, the federal arsenal at Harper's Ferry, Virginia began producing rifles. The U.S. Model 1803 Rifle featured a half-stock with a thirty three-inch barrel of .54 calibre. Half the barrel's length was round and the other half octagonal in shape.
The Harper's Ferry rifles had brass fittings and a large compartment on the stock to hold the patches which accompanied the ball down the barrel to assure a snug fit. Like muskets, this rifle was fired using a flintlock system of ignition. Unlike the musket, however, the rifle had no bayonet, giving its user a distinct disadvantage in close combat. Over 4,000 Model 1803 Rifles were manufactured at Harper's Ferry between 1803 and 1807. Between 1807 and 1808, the U.S. Government issued contracts to private manufacturers to produce rifles based on the Model 1803 weapon. One of the common visible differences between the rifles manufactured at Harper's Ferry and the so-called "Contract Model 1807" was that the latter often sported a full wooden stock. Due to increased wartime needs, production of the Model 1803 resumed at the Harper's Ferry aresenal in June 1814 and continued until 1820.