Min"ie ball` (?). [From the inventor, Captain Mini'e, of France.]
A conical rifle bullet, with a cavity in its base plugged with a piece of iron, which, by the explosion of the charge, is driven farther in, expanding the sides to fit closely the grooves of the barrel.
© Webster 1913
While there are many accounts of troops charging bravely into a "hail of grape" there is little fact in this. Grape shot was used very little on the land battlefield during the Civil War. The ammunition encountered by the soldiers was called canister, one of the war's most deadly rounds. Canister was basically a tin can packed with sawdust and musket balls which, when fired, spread out and turned the artillery piece into a giant shotgun. At close range against massed infantry this round was devastating, cutting huge swaths through the attacking men.
Grape shot was widely used in 18th century wars, but by the time of the American Civil War, grape was primarily used by navel gun crews. Similar to canister, grape shot consisted of metal balls, but unlike canister which fired 76 balls, a round of grape shot consisted of nine or so balls and were usually not packed in cans. A standard round consisted of three tiers of three 2 inch diameter balls separated by iron plates and held together by a central rod which connected the top and bottom plates. Another design consisted of an iron bottom plate with a central pin around which the balls were stacked. A cloth bag, usually of canvas, covered the balls which was in turn lashed around with a cord. The resulting round of ammunition looked like a bunch of grapes -- hence the name "grape shot". Grape shot, like canister, would spread out with a shotgun effect once leaving the muzzle of the gun, though with a much greater range than canister