Part 5/9:
Upon entering the bomb, the uranium-235 weighed around 145.5 pounds (65.5 kilograms), comprising both the projectile and target rings. The bomb was encased in a 6.5-inch (170-millimeter) smoothbore gun barrel, which facilitated the mechanics of the detonation sequence.
In terms of activation, the fusing systems utilized a combination of barometric sensing ports that helped the bomb identify its altitude, and radar altimeters that further ensured accurate detonation height.