The Germans have produced another rather striking innovation for higher
velocity ammunition, in keeping with their hollow-charge projectiles, the Gerlich
taper-bored gun and the ammunition for it. This is a streamlined shell with
guide and rotating bands both designed to fall to pieces and release themselves
from the shell while in flight with the object of perfecting the air-form to decrease
resistance. At present these shells are known to be of 105-mm (4.13 in) and
150-mm (5.90) caliber, HE (see accompanying sketches).
a. General Description
In addition to being similar in general design, both projectiles are HE and
are fitted with nose-percussion fuze type AZ-23v, the detonator being similar to
those for the usual type of German HE shell. Beneath the fuze is a booster located
by a booster holder. In the case of the 105-mm shell, it is type gr. Zdlg. C/98 Np,
and for the 150-mm shell it is type Zdlg. 36. Beneath the booster is a smoke pellet.
Both projectiles are painted yellow.
b. Disintegrating Bands
A detachable guide band forms the bourrelet of the projectile. This band
has three cuts extending almost completely through the band and spaced 120° apart.
The complete band, which is a push fit on the shoulder, is held in position by three
ball bearings. These are seated in three cavities spaced equally around the
periphery of the shoulder of the shell and project into cylindrical drillings through
each segment of the guide band. The drillings are threaded towards the outer
circumference, and the ball bearings after insertion, are finally located by screws
which seat the outer surface of the bearings. After insertion of the balls and the
positioning of the three screws, the guide band is firmly attached to the shell body.
If the three cuts in the guide band were completed, each segment, together with its
retaining ball, would be free to fall away from the shell body.
The rotating band holder is located at the base of the shell, which is keyed
to receive it. The holder itself is in three detached segments held in position only
by the soft iron rotating band. Movement is prevented by three cylindrical pieces
fitting into cavities located in the shell body and the driving-band holder. There
are also three cylindrical pins between the segments.
c. Functioning
It is believed that after leaving the gun the guide band and the rotating band
holder are each split into three separate segments which, together with the ball
bearings, pins and cylindrical pieces retaining them, are flung off. The remaining
projectile is then of much better aero-dynamic shape than is possible with a
conventional projectile.
d. Characteristics
The following are the general characteristics of these projectiles:
105-mm | | |
Weight of projectile | | 10.5 kg (23.1 lb) |
Weight of bursting charge | | 0.5 kg TNT |
Stencillings on body | | 14 764 R8 (smoke pellet type) Hi 9.8.42 Ma |
|
150-mm | | |
Weight of projectile | | 28.7 kg (63.14 lb) |
Weight of bursting charge | | 3.4 kg TNT |
Stencillings on body | | 14 186 R9 (smoke pellet type) Hi 9.8.42 Ma Z 3033 |
It is worth noting that the usual weight for the 105-mm shell is about
33 pounds, and the weights of the ordinary 150-mm projectiles, 88 and 95 pounds.
By lightening the projectile and eliminating the bands, a substantial increase in
velocity and range is probably attained.
e. Packing
The 105-mm projectile is packed in a wooden crate. The 150-mm projectile
may be packed in a wooden crate or a wicker basket.
It is not known with which equipment these projectiles are intended to be
used. Neither cartridge cases nor charges have as yet been identified. It should
be noted that the disintegration of the guide band and rotating band holder is
likely to cause some danger in an area forward of the muzzle.