Construction: The fuze body, gaine, magazine carrier, and nose cap are made of alumi-num. The two time rings are made of brass. A hollow spindle protrudes up from the fuze body, over which are fitted the lower (movable) and upper (fixed) time rings. The nose cap threads onto this extension and holds the upper time ring in place. Housed within the hollow spindle are the striker, creep spring, and initiating cap or primer. Halfway up the side of the hollow spindle is a flash port leading to the upper time train. There is a tooth rack machined around the upper edge of the lower time ring for automatic setting.

The gaine threads into the lower end of the fuze body.

Operation: As the round feeds into the gun, a rack engages the teeth of the lower time ring, which is rotated about its axis by the meshing of these gears, setting the fuze. When the gun is fired, the force of set-back causes the striker to pierce the primer. The flash from the primer passes to the upper time ring, and in turn, to the lower. The flash from the lower time ring sets off the relay pellet and the black powder, which flashes down to the gaine.

Figure 440 – 40-mm Powder Time Fuze.