The Minié Ball None of the Union army’s weaponry proved more vital than a French innovation by Captain Claude Minié. In 1848, Minié created an inch-long bullet that was rammed down a rifle barrel and would spin as it left the muzzle. The spin gave the bullet greater distance and accuracy than bullets fired from smoothbore weapons. Bullets caused more than 90 percent of battle wounds. Picture Research Consultants & Archives.