Construction: The fuze is built with a brass nose piece, an aluminum midsection, a fixed and movable powder ring, and a base section which houses a black-powder magazine in the rear end and supports a central spindle which houses the fixed firing pin. The spindle and base section are made in one piece. The nose piece is a hollow truncated cone con-taining four vent holes forward and threaded (R.H.) internally, rear, to fit forward end of the aluminum midsection. The aluminum mid-section has four vents forward and a threaded (R.H.) opening located centrally. At the rear of the threaded opening, the aluminum piece has a longitudinal recess to take a small coiled spring whose purpose is to prevent the freezing of the movable primer carrier, which is partially housed in the alumi-num midsection. A narrow lip around the base circumference of the midsection fits into a groove on the upper surface of the fixed (upper) time ring and forms a seal. The rear end of the movable primer carrier is housed in the forward end of the spindle. The primer car-rier is made of a small brass cylinder, into the top of which is threaded a small weight. The primer is carried in the lower part of the carrier and rests on an internal lip. Sur-rounding the cylinder and secured by a tight friction fit, is a split brass collar which rests upon an internal shoulder in the upper end of the spindle. The movable (lower) time ring has the time settings (0 to 30 seconds) in increments of 1/5 second. A segmented brass friction washer is keyed to the spindle and holds the fixed time ring in position.

Operation: Upon firing, set-back causes the primer carrier to move down out of the split collar and onto the firing pin. The flash ignites the black-powder delay in the upper time ring, and after the set delay period the black powder magazine is ignited.

Figure 442 – 30-Second Powder Time Fuze.