The Henry Repeating Rifle was a truly revolutionary development in firearms technology. It was not the first repeating rifle, but it was the best of a emerging class of new arms, reliable in function and very fast to shoot (much faster than the contemporary Spencers). The Henry used a simple toggle lock locking system, with a single throw of its lever performing all the elements necessary to reload and recock the action.
The Henry’s quick action was coupled with a 15-round magazine, more than double what the Spencer offered. It fired the .44 Henry rimfire cartridge, which threw a 216 grain bullet at about 1125 feet per second (this would change to 200 grains at 1200 fps within a few years). This was substantially less powerful than a heavy muzzleloader charge, but the volume of fire more than made up for it. Within 200 yards, the Henry could produce a devastating volume of fire.
The Henry was only produced for about 5 years (1862 – 1866), with about 12,000 manufactured in total. The rifle was made almost exclusively in a standard rifle pattern, with a 24 inch barrel. Some were later cut down into carbines, though. While the US military rejected the Henry for a variety of reasons, nearly all of the guns produced before the end of the war did actually see military service, with state units or individuals who supplied their own arms. In the few engagements where Henry rifles were present in substantial numbers, they proved to be a significant force multiplier.