M1819 Hall rifle

The M1819 Hall rifle was a single-shot breech loading rifle designed by John Hancock Hall, patented on May 21, 1811, and adopted by the U.S. Army in 1819. It was preceded by the Harpers Ferry Model 1803. It used a pivoting chamber breech design and was made with either flint-lock or percussion cap ignition systems. The main years of production were from the 1820s to the 1830s at the Harpers Ferry Arsenal. This was the first breech loading rifle to be adopted in large numbers by any nation's army, but not the first breech loading military rifle - the Ferguson rifle was used briefly by the British Army in the American Revolutionary War. Breech loading rifles remained overshadowed by common muskets and muzzle loading rifles so prevalent in the early 19th century. The early flintlocks were mostly converted to percussion ignition.

Comparative trials
United States Army inspectors conducted trials by having a 38-man infantry company fire at a 100 yd target for ten minutes at their own speed.

Production history
The original flintlock model had a 32.5 inch barrel rifled with 16 "clockwise" (right-hand) grooves making a turn in 96 inches. The muzzle was reamed to a depth of 1.5 inches and had an appearance of a smooth bore. Overall length was 52.5 inches and weight without bayonet was 10.25 pounds. The rifle fired a .525 ball weighing 220 grains (one-half ounce), using a 100-grain powder charge and 10 grains of fine powder primer.

The carbine design was produced beginning in 1833, using a smooth-bore barrel of 23 inches in length. It had an overall length of 43 inches, weighed 8 lbs, and was the first caplock firearm adopted by the U.S. Army. The following year, a carbine in .69 caliber was introduced for the Regiment of Dragoons, with a second run in 1836-1837. Barrel length was reduced to 21 inches in 1840, and a "fishtail" breech lever design credited to U.S. Army Captain James Huger was also introduced for the next 7,000 carbines, including the M1842 carbine, the final "regulation design" of the series.

In 1843 the Hall-North carbine, variously known as the M1843 and the "improved 1840", featured a side-mounted Henry North-Edward Savage breech lever. 11,000 Hall-North carbines were manufactured with a 21-inch, .52 caliber barrel. The Hall production line at Harper's Ferry closed in 1844, but between 1843 and 1846, 3,000 M1843 carbines were also manufactured by Simeon North.

Action
The back several inches of the "barrel" (the chamber) is a separate piece that pivots upwards from the front for reloading. In essence the weapon was still loaded front to back, but in a short section, similar in concept to loading a cylinder of an early cap and ball revolver.

The development was primarily the work of Hall, who had been working on a design in the first two decades of the 19th century, receiving critical patents during the time. The work caught the interest of Army, which lead to the contract at the end of the latter decade. The breech loading design was made possible by his focus on using carefully machined components to form a seal, but still allowing enough tolerance for the breech to be opened easily. The Hall rifle offered a significant increase in rate of fire over muzzle-loading rifles and muskets. However the design suffered from a gas leak around the interface of the removable chamber and the bore, resulting in the necessity of a heavier powder charge that still produced much less muzzle velocity than its muzzle-loading competition. No serious efforts were made to develop a seal to reduce the loss of gas from the breech. The penetrating ability of its .52-caliber ball for the rifle was only one-third of that of the muzzle-loaders, and the muzzle velocity of the carbine was 25 percent lower than that of the Jenks "Mule Ear" carbine despite having similar barrel lengths and identical 70-grain powder charges.

Thousands of rifles were made, though the troops and many leaders preferred the simplicity and lower costs of muzzle loaded weapons. However, the advantages were clear, and breech loading designs would grow to dominate rifle procurement after the Civil War. Many of the lessons learned by Hall would benefit designers of the next generation of breech loaders such as the Sharps rifle (1848), Spencer carbine (1860) and others.

The Halls were used against Indians and in smaller conflicts. Some saw service in the Civil War; however, by this time many rifles were worn out over 30 years of use.

As part of the process, Hall built his own shops and machinery at Harper's Ferry, and along with inventing this weapon, he invented many machines paving the way for uniform manufacturing of weapons with interchangeable parts. The ruins of his shops are still visible today.