The standard light gun-howitzer of the German Army is the 105 mm
(see figs. 1 and 2). It is directly comparable to our 105-mm howitzer
and to the British 25-pounder. The following table of characteristics
shows the relationship between the German gun-howitzer and its American counterpart:
|| German 105-mm|
|| U.S. 105-mm|
|Maximum muzzle velocity||
||1,542 ft per sec.||
||1,550 ft per sec.|
|Weight of standard H.E. shell ||
|Weight of bursting charge||
It must be noted, however, that the performance of the German gun-howitzer is
rendered less effective by a standard use
of charge 5 rather than charge 6. This
reduces the maximum muzzle velocity from 1,542 feet per second to 1,283 feet per
second, and the maximum range from 11,674 to 10,007 yards. The use of semi-fixed
ammunition cuts down the maximum rate of fire and further reduces the effectiveness
of the weapon.
The German gun-howitzer may either be tractor-drawn or horse-drawn. In
tractor-drawn units a light tractor is used; when the piece is horse-drawn,
the howitzer and limber are pulled by a six-horse team.
2. DESCRIPTION OF COMPONENT PARTS
The tube of the German 105-mm gun-howitzer is long, and of
monobloc construction, with the counter-recoil cylinder above it. The
elevating mechanism permits the piece to be used as either a gun or a
howitzer, as the occasion dictates. Its high elevation
and the use of semi-fixed ammunition give it the characteristics of a
howitzer. On the other hand, the long tube allows a high muzzle velocity, and
the long split trail gives the piece good stability when it is to be
used as a gun.
|Figure 1.—German 105-mm Gun-Howitzer, Left Side View (trails spread and spades locked in position).|
The breech mechanism is of the horizontally sliding type, and simply
designed. Built-in safety devices
allow the firing mechanism to operate only when the breech block is
in the fully open or fully closed position. Also, a hand-operated safety
device is provided.
|Figure 2.—German 105-mm Gun-Howitzer, Rear View (traveling position)|
The recoil and recuperator systems are of the hydro-pneumatic type. The
elevating mechanism is a well protected unit; it is entirely enclosed
except for the elevating arc and its pinion. The total elevating arc
is 47 degrees and 37 minutes. Since the worm and worm wheel are permitted
to move against Belleville springs, the recoil and counter-recoil
force is absorbed.
The traversing mechanism is of the nut-and-screw type, and is almost
completely enclosed. The total traversing arc is 56 degrees and 14 minutes,
or 28 degrees and 7 minutes, to the right and to the left.
The bottom carriage is of very complicated design, and has more parts
than the bottom carriage of our 105-mm howitzer.
In design and general construction, the optical fire-control equipment is similar
to the corresponding equipment used on the American 105-mm howitzer.
The standard high explosive shell used in the German gun-howitzer consists of
a shell case, primer, and propelling charge of nitroglycerine powder (divided
into five zones and contained in cloth bags). This powder is not flashless.
The projectile consists of a two-piece steel shell, similar in shape to our
105-mm M-1 shell, and has a rotating band of
copper (on a steel backing) that is rolled into place.
A super-quick percussion fuze, or a time-and-percussion fuze, is provided, and
a booster fits in a pocket below the fuze cavity.
 Howitzers with semi-fixed ammunition have propellant charges which
are divided into sections called "zones." When a range has been determined, one
or more zones can easily be removed from the shell case, so as to give the
desired charge for the range in question. The German gun-howitzer, which has
six zones, uses any combination of the first five as the standard charge; whereas
the American howitzer, which has seven zones, uses any combination of the first
six as the standard charge.