The German 75-mm recoilless gun described in Tactical and Technical
Trends No. 26, p. 15 has been reinforced with a recoilless, 105-mm, rifled howitzer,
10.5-cm L.G. 40 (Leichtes Geschutz airborne gun). Like the 75-mm gun, it has
an open breechblock with a venturi tube attached, and "shoots both ways", producing
a terrific blast to the rear. While data as to the ammunition is not available, it
seems reasonable to suppose that the projectile may weigh about 25 pounds. The
complete howitzer weighs only 900 pounds. With a range of 6,660 yards, this gun
appears to be a formidable air-borne or mountain weapon.
* * *
|Caliber|| ||105-mm (4.13 in)|
|Weight, total, approximately||900 lbs|
| Howitzer, breech ring and venturi tube||500 lbs|
| Axle assembly without wheels||160 lbs|
| Trail||86 lbs|
| Upper carriage||58 lbs|
| Shield||86 lbs|
|Length of howitzer (overall)||6 ft 3 in|
|Length of barrel||4 ft 6 1/4 in|
|Length of rifling||2 ft 7 1/4 in|
|Rifling||32 lands and grooves, righthand twist|
|Muzzle Velocity:|| |
| Firing H.E.||1105 fs|
| Firing hollow charge||1224 fs|
|Maximum range||6660 yds|
|Effective range with hollow charge||1665 yds|
|Elevation||-15° to +40°|
|Traverse||40° right, 40° left|
|Height of trunnions in firing position (on tripod)||2 ft 8 1/2 in|
The tube is of monobloc steel construction. On the breech end, interrupted
collars provide for attachment of the tube in the breech ring. A keyway is cut
longitudinally at the breech end, twelve o'clock inside the chamber, to receive
a key on the cartridge-case which houses the primer.
The trunnions and the elevating arc are attached to the breech ring which
is recessed to receive the barrel locking lugs. A hole, housing a percussion
firing mechanism is located at twelve o'clock approximately one inch from rear
face and lines up with a hole in the barrel to receive the firing pin.
The breechblock, of the venturi type, is attached to the rear face of the
breech ring by a pin at about four o'clock. A horizontal handle situated at about
ten o'clock operates a spring-loaded locking catch and also serves as a lifting
grip to rotate the breech block about the pin into open position. A replaceable
steel bushing is screwed into the front end of the venturi tube. The approximate
dimensions of the venturi are: Throat diameter, 3 5/8 inches; exit diameter,
11 inches; length, 1 ft 8 1/2 inches.
Carriage and Trail
The lower carriage is formed by the trail which is of box-type, welded
construction, and has a bushing at the front end to receive a perpendicular pin
fixed to the axle. A lever fitted to the axle raises the wheels off the ground after
a tubular steel bipod has been swung down to firing position. In travel this bipod
is swung back and hooked to the bottom of the trail. The legs of the bipod are
The upper carriage is constructed of welded sheet steel. The pintle is
fixed to the bottom of the upper carriage and fits into a bushing in the trail.
Axle and Suspension
The axle is tubular steel, and the suspension is of the parallelogram type
acting on compression helical springs housed in the axle.
Traverse and Elevation Mechanism
The traverse and elevation handwheels are fitted to the left side of the
upper carriage. Elevation is by means of segment and spur gear and traverse is
effected by means of worm and worm-gear segment.
The howitzer may be drawn by a vehicle. In towing position the piece is
elevated to maximum elevation and locked to the rear of the trail by means of a spring
loaded catch fitted to the trail; the towing lunette is fixed to the bottom of the muzzle.
Carrying handles are fitted to both sides of the muzzle, both sides of the
barrel in front of the breech ring and at the rear of the venturi tube. The barrel
assembly can be split into two loads, barrel one load and breech ring and
breechblock (venturi tube) as the other load.
The upper carriage becomes a load by lifting pintle out of trail. The trail, a
separate load by lifting off from perpendicular pin fixed to the center of the
axle, and the axle assembly is taken as one load. The wheels which are easily
removed, can be taken as a separate load. The shield, hooked on to lugs fitted
at the front of the upper carriage, is likewise easily removable.