Pumpkin bomb

Pumpkin bombs were large conventional aerial bombs developed by the Manhattan Project and used by the United States Army Air Forces against Japan during World War II. Their physical characteristics closely matched those of the Fat Man plutonium-based nuclear bomb, with the same ballistic and handling characteristics, but the payload was 6,300 pounds (2,900 kg) of conventional high explosives. While their main purpose was for testing and training in preparation for the 509th Composite Group potentially delivering a Fat Man on a target, post-war analysis deemed the pumpkin bombs to have been effective weapons in their own right. The name "pumpkin bomb" used in official documents derived from the large, fat ellipsoidal shape of the munition casing required to enclose the Fat Man's spherical "physics package" (the plutonium implosion nuclear weapon core), compared to the usual slimmer cylindrical shape of conventional bombs.