The Probert Encyclopaedia of Warfare

BLUNDERBUSS

The blunderbuss was usually a short carbine or pistol intended as a defensive weapon which fired a large load of heavy shot at close ranges. It was of a very wide bore with a bell-shaped muzzle capable of holding a number of slugs or bullets. Although now obsolete, the principal of the blunderbuss is today used in the sawn-off shotgun which inflicts heavy wounding at close range without the need to aim more than approximately.
Research Blunderbuss