The 8 cm Wgr. 39 consists of a nose fuze, front cap, rear body, and tail assembly. The body, which is separated from the cap at the ogive, has a standard shape and TNT filling. The cast nose cap fits over a cylindrical boss, concentric with the longitudinal axis of the projectile. This cap is secured to the boss by four shear pins that extend through the cap and the boss. The seam where the two parts are joined is then shellacked to form a watertight seal.
An impact type, nondelay fuze is screwed into the cap; inside the cap is a plastic container of about 1 1/2 ounces of smokeless powder. Under the charge, screwed into the projectile body, is an iron plug with a small axial hole through it. This plug separates the smokeless powder charge from the combination delay pellet and booster which is in an aluminum container.
The tail assembly is a standard type, having the usual base charge, ring increments, and fin assembly.
Upon impact, the nondelay fuze ignites the smokeless powder charge, sending a flash through the hole in the separating plug, setting off the delay pellet. The explosion from the first charge shears the pins holding the nose cap to the projectile body, and throws the shell from 5 to 10 feet into the air. In the meantime, the booster detonates the main TNT bursting charge at approximately the moment when the projectile is at the height of its bounce. This gives the effect of an air burst without the use of a precision time fuze. Height of the burst is governed by the angle of the shell axis with the ground at the time of impact.
KEY TO PARTS:
(A) Propellant increments
(B) Propellant cartridge
(C) Projectile body
(D) False ogive
(E) Point ignition fuze—Wgr. Z 38 st
(F) Booster well
(G) Booster capsule
(H) Delay type detonator
(I) Paper washer
(J) Paper diaphragm
(K) Plastic washer
(L) Booster well adapter
(M) Ejector capsule
(N) Ejector capsule igniter
German: p. 309 (August 1, 1945)