On July 8, 1856, Charles E. Barnes received U.S. Patent No. 15316 on a Machine Gun:

This was one of the first crank operating guns that could fire as fast as the crank could be turned, and had the design been pursued it would have resulted in a functional machine gun before the Civil War. It was not until Richard J. Gatling’s design, patented November 4, 1862, that a truly functional automatic weapon was available: