US Bomb, 100 lb GP, Mk 1 Mod 2, 3, Mk 4 Mod 1-4
Mk 1 has two sheet steel castings welded together, the bomb having a "tear drop” shape. Mk 4 is a single-piece steel forging; cylindrical, with ogival nose.
Mk 1 is horizontally suspended by two lugs welded on the body; it may have single lug or trunnions on the band. Mk 4 has two lugs welded on the body 14 inches apart; with a single lug welded on the opposite side.
Grey over all with a four-inch yellow disc between the two lugs, indicating HE. The color may be yellow over all.
Mk 1 has four vanes which pass down over the body and are welded to a tail cone. The vanes are fastened to the body of the bomb by screws and are braced by two sets of bar struts riveted to the vanes. Mk 4 has four vanes welded to a sleeve which is secured to the bomb body with a locking nut. Box-type internal struts are welded to the vanes. Mk 4 Mod 4 pictured above.