A sketch showing the details of the hollow-charge round for the
German 7.5-cm KwK (75-mm tank gun) accompanies
this report. The German nomenclature for this ammunition
is 7.5-cm Pz. Gr. Patr. 38 KwK.
The round is of the fixed type. The cartridge case and the weight and type of
propellant are similar to those for the other types of 75-mm antitank
gun ammunition. The shell is fitted with a threaded hemispherical cap into
which is screwed a small nose percussion fuze. From the nose fuze, a central
tube runs down to a booster which is situated in the base of the shell. This
booster consists of a detonator set in penthrite wax, the whole being
contained in a perforated container. The bursting charge consists of
three blocks of Hexagen (Trimethylene Trinitramine) the front one of which is
concave, as shown in the sketch. The blocks are contained in waxed paper and are
cemented into the shell.
The operation of the Aufschlag Zunder or percussion fuze (A.Z. 38-type
fuze) is simple. The striker is held off the detonator assembly by six centrifugal
segments which are surrounded by an expanding spring ring. After the shell has left
the gun, centrifugal force causes the clock spring and the safety blocks to
open, thus freeing the striker. Upon impact, the striker is driven onto
the detonator. The detonation passes down the central tube to initiate the
booster. This in turn initiates the bursting charge.
The shell is painted white and has black markings. The weight of the shell
is 4.5 kilograms, and that of the bursting charge 450 grams.
Comments: This is another instance of the use of hollow-charge
ammunition to increase the armor-shattering effect of a gun of comparatively low
muzzle velocity. No data is available at this time concerning the performance
of this type of projectile against armor at various ranges.