Text copied from Bulletin#59 german hand- & riflegrenades, Mar.7 1944 :
Data: Overall length: 6.4inches, Maximum diameter 1-3/16inches, Color: Front half is black- Back half is aluminium, Total weight: 8.8ounces, Filler: TNT, Weight of filler: 1.75ounces, Range: 50 yards.

Description: This grenade is fired from the rifled 3cm. discharger cup (Schiessbecher) which can be fitted to most types of German rifles. It is constructed in two parts, the head and the stem.

photo a good friend

The head is seamless steel tube with the forward portion containing a hollow charge cone and the explosive filling, being closed at the forward end by a light ballistic cap. The main filling of TNT is poured around the cone and there is a cavity formed in the after part of the main filling in which the exploder of penthrite wax is inserted.
The stem is made of light alloy or aluminium and is screwed onto the head of the grenade. The stem is divided into two compartments, the lower containing the fuze, the upper the gaine. In the septum is a small flash pellet held in place by a perforated screw plug. The gaine consists of a light alloy case into which is inserted a light alloy top hat containing the detonator, the space between being filled with penthrite wax. A pre-engraved driving band is formed around the stem 6mm. from the rear.

(Drawing on the right © Evgeny)

The fuze is in the after portion of the stem and consists of a striker over the top of which fits a retaining spring with four prongs bent downward into grooves in the striker body. Around the striker body is an arming collar which has two grooves cut on the inside. An arming spring is compressed between a lip on the arming collar and a second collar at the bottom of the striker body. Around the inside of the arming collar and resting on the striker body is a steel tape which acts as an additional safety device and prevents any possibility of the fuze being accidentally armed when screwing on the base plug.

The entire assembly is closed by a base plug which positions the fuze by a stem which fits in the rear of the striker body.

Operation: On firing, the shock of discharge causes the arming sleeve to set back against its spring. The four prongs of the retaining spring are forced out of the lower groove in the arming sleeve and engage in the upper groove, retaining the arming sleeve in its lower position. This allows the steel tape to unwind and the striker is then free to move forward on impact firing the gaine.