The original Henry rifle was a sixteen shot .44 caliber rimfire, lever-action, breech-loading rifle patented by Benjamin Tyler Henry in 1860 after three years of design work. The Henry was an improved version of the earlier Volition Repeating Rifle. The Henry used copper (later brass) rimfire cartridges with a 216 grain (14.0 gram, 0.490 ounce) bullet over 25 grains (1.6 g, 0.056 oz.) of gunpowder. Production was very small (150 to 200 a month) until middle of 1864. Nine hundred were manufactured between summer and October 1862; by 1864, production had peaked at 290 per month, bringing the total to 8,000 manufactured. By the time production ended in 1866, approximately 14,000 units had been manufactured.
For a Civil War soldier, owning a Henry rifle was a point of pride. Letters home would call them "Sixteen" or "Seventeen" Shooters, depending whether a round was loaded in the chamber. The US Government purchased about 3,140 (early versions with inspector marks) in late 1863 to early 1864, mostly for Cavalry units. Just 1731 of the standard rifles were purchased by the government during the Civil War. The relative fragility of Henrys compared to Spencer repeating rifles hampered their official acceptance. More Henrys were purchased by soldiers than by the government. Many infantry soldiers purchased Henrys with their reenlistment bounties of 1864. Most of these units were associated with Sherman's Western Troops.
When used correctly, the brass framed rifles had an exceptionally high rate of fire compared to any other weapon on the battlefield. Soldiers who saved their pay to buy one believed it would help save their lives. Since tactics had not been developed to take advantage of their firepower, rather than in regular infantry formations Henrys were frequently used by scouts, skirmishers, flank guards, and raiding parties. To the amazed muzzleloader-armed Confederates who had to face this deadly "sixteen shooter", it was called "a rifle that you could load on Sunday and shoot all week long." Those few Confederate troops who came into possession of captured Henry rifles had little way to resupply the special ammunition used by the weapon, making its widespread use by Confederate forces impractical. The rifle was, however, known to have been used at least in part by some fifteen different Confederate units in Louisiana, Texas, and Virginia, as well as the personal bodyguards of Confederate President Jefferson Davis.