EMPLOYMENT: Mechanical Impact Nose Fuze for German H.E. 5-cm Mortar Bomb. (See fig. 591.)

DATA:

Overall length: 2.563 inches (with gaine).

Overall length: 1.563 inches (without gaine).

Maximum diameter: 1.250 inches.

Threaded length: 0.375 inch.

Number of thread: 5 RH.

CONSTRUCTION: The fuze body is aluminum and houses a steel primer pocket and a brass retaining spring. Within the fuze there is a striker secured to a cup-shaped plunger in the head and a striker guide tube which leads to a primer in the base. The tube is at-tached to the primer pocket and is separated from the striker plunger by a creep spring. The fuze is kept in the unarmed position by nine steel balls located between the striker plunger and the primer pocket. These balls are arranged around a central set-back slee-ve which is held in position by a set-back spring. The set-back sleeve has a flange for-med around the rear end to engage with the tongues of the retaining spring (fitted in the primer pocket) when the fuze is armed.

ACTION: Upon discharge, the set-back sleeve is dirven down compressing the set-back spring and engaging the tongues of the retaining spring. This creates a clearance in the striker plunger into which the nine steel balls are forced by a creep action during flight. In this position, the fuze is armed with only the creep spring preventing contact of the striker with the primer. There is a brass closing disk over the head of the fuze which pre-vents air pressure from functioning the fuze in flight. Upon impact or graze, the creep spring is overcome and the striker pierces the primer.

REMARKS: According to a German firing table, the fuze can be made more sensitive in order to function in mud or snow, by removing the brass closing disk. Another fuze which can be used on the 5-cm mortar is the plastic fuze, Mgr.Zt., which differs internally form the Wgr.Z. 38.

The fuze, Wgr.Z. 38 is interchangeable with all German 5- and 8-cm mortars. It is belie-ved the German nomenclature, stamped near the base, designated the model number and the type of metal used in the fuze construction:

Wgr.Z. 38 – Aluminum.

Wgr.Z. 38 st – Steel.

Wgr.Z. 38 z – Zinc.

Wgr.Z. 38 – Ausf. C.

All of the fuzes are of the set-back armed, instantaneous ignition type.

Figure 591 – Wgr.Z. 38