In 1848, Walter Hunt of New York patented his "Volition Repeating Rifle" incorporating a tubular magazine, which was operated by two levers and complex linkages. The Hunt rifle fired what he called the "Rocket Ball," an early form of caseless ammunition in which the powder charge was contained in the bullet's hollow base. Hunt's design was fragile and unworkable, but in 1849, Lewis Jennings purchased the Hunt patents and developed a functioning, if still complex, version which was produced in small numbers by Robbins & Lawrence of Windsor, Vermont until 1852.