The US military experimented with a wide variety of breechloading carbines during the Civil War. One of these that got a bit of a head start on the others was the Smith carbine, patented in 1855-57 by Gilbert Smith, a physician from New York. He contracted with Poultny & Trimble of Baltimore - a major arms and military accoutrements dealer - to market the gun, and he received his first military order in February of 1860. That first order was on for 300 guns, but it meant that the design was a known quantity to the military when war broke out. Throughout the war a series on contracts were written for a few thousand Smith carbines as a time, with final deliveries made in June 1865 and a total of just over 31,000 delivered to the military. Prices steadily dropped form $35 per gun before the war to just $23.50 by the final contract.

The Smith was a break action design using a cartridge made of India rubber. It was a capping breechloader, meaning that ignition was provided by a traditional primer on the side of the action, and not through a primer integral to the cartridge. This rubber system was a reliable obturator, and the Smith received generally positive reviews from cavalry units that used it in combat.