An account of a new and powerful tapered-bore 75-mm AT gun made by
the Rheinmetall factory, the 75/55-mm (2.95-in/2.17-in) Pak 41, has recently
become available through Allied sources. The gun has a curious bore; the rear
part is cylindrical and rifled; the central part, tapered and unrifled, and the muzzle
section -- 27.6 inches -- cylindrical and unrifled. The weight of the powder charge
fired is 95 per cent of the weight of the projectile. With an estimated velocity of
approximately 4,000 f/s, and a penetration of 5.94 inches of homogeneous armor
at 1,000 yards, the gun is most formidable.
The 75-mm Pak 41, one of the latest German antitank guns to be brought
into service, is the third* of the Gerlich or tapered-bore weapons introduced. In
issue No. 7, p. 3 of Tactical and Technical Trends, reference is made to the use
of this principle in the 42-mm Pak 41. A 75-mm tank gun, the 7.5-cm Kw.K 41, is
also known to exist, and it is very probable that this weapon too is of the
tapered-bore variety. The caliber of the 7.5-cm Pak 41 at the breech is 75 millimeters
(2.95 in), while at the muzzle it is reduced to 55 millimeters (2.17 in). The
reinforced breech is of the vertical wedge type, and is semiautomatic. There is a
muzzle brake. The weapon is very long, low and sturdy in appearance. The carriage
which has a split trail, is unusual but extremely simple. The cradle is attached
to the shield, which forms the basis of the carriage, by what is, in effect, a spherical
universal joint. The cradle itself is cylindrical, and covers the whole of the rear
half of the barrel. The gun is sighted up to 1,500 meters (1,635 yards), and the
sight has four scales for use according to the actual muzzle velocity of the gun,
which drops considerably owing to wear. The life of the barrel is provisionally
estimated as 500 to 600 rounds.
The shield is composed of 2 1/4-inch plates bolted together with the barrel
installed in a ball mount.
The elevating mechanism, of the sector type, is on the right-hand side of
the cradle. The traversing mechanism is of the screw type and is on the left.
There is no equilibrator. The buffer is hydraulic, and the recuperator is spring
type. The wheels are metal with solid rubber tires. Traction is motorized. The
axle is under-slung with torsion-bar suspension, which is automatically cut out
when the trails are opened. Pneumatic brakes, controlled by the driver of the
tractor, are fitted.
b. Gun Data
|Estimated muzzle velocity|| ||4,123 |
|Length of barrel (approx)||170 in|
|Weight in action||1.4 tons (British long)|
|Elevation||-10° to +18°|
|Height of axis of bore at 0° elevation||34.6 in|
|Length of recoil (approx)||27.6 in|
Fixed ammunition is used with an AP tracer projectile of Gerlich design
(see accompanying sketch). The AP round is known
as 7.5-cm Pzgr. Patr. 41 Pak 41
(Armor-piercing shell Model 41 for Pak 41).
The projectile consists of the outer case (1), the tungsten carbide core (2),
the screw-head (3), the ballistic cap (4), and the tracer (5). The outer case has a
forward and a rear skirt. Only the forward skirt is perforated. The screw-head
is made of mild steel.
The propellant charge is diglycol tubular powder, while the igniter is of
pyroxylin porous powder.
There is also an HE round (7.5-cm Sprgr. Patr) (HE shell Model 41
for Pak 41) as in the cases of the 2.8-mm s.Pz.B (antitank gun) 41
and the 4.2-cm Pak 41, but no details of this ammunition are known.
The following are brief specifications of the AP ammunition:
|Total weight of round|| 16.65 lb|
|Total length of round|| 29.8 in|
|Weight of projectile|| 5.68 lb|
|Weight of tungsten carbide core || 2.01 lb|
|Diameter of core|| 1.16 in|
|Weight of propellant charge|| 5.4 lb|
The following figures for penetration of homogeneous armor by this weapon
firing the AP projectile have been estimated:
|| Thickness of armor in inches |
| 500|| (6.67 in)|| (5.75 in)|
| 1,000|| (5.94 in)|| (5.12 in)|
| 1,500|| (5.28 in)|| (4.49 in)|
| 2,000|| (4.63 in)|| (3.94 in)|
*The other two are: the 2.8-cm (1.10 in) heavy antitank rifle and
the 4.2-cm (1.65 in) light antitank gun.