Minié ball
The Minié ball, or Minie ball, is a type of hollow-based bullet designed by Claude-Étienne Minié for muzzle-loaded, rifled muskets. Invented in 1849 shortly followed by the Minié rifle, the Minié ball came to prominence during the Crimean War and the American Civil War where it was found to inflict significantly more serious wounds than earlier round musket balls.