 Roughly 90% of the battlefield casualties in the American Civil War (1861-1865) were caused by Minié balls fired from rifled muskets.A similar bullet called the Nessler ball was also developed for smoothbore muskets.Between 1854 and 1857, Sir Joseph Whitworth conducted a long series of rifle experiments, and proved, among other points, the advantages of a smaller bore and, in particular, of an elongated bullet.