7.5 cm KwK 42

The 7.5 cm KwK 42 L/70 "(7.5 cm Kampfwagenkanone 42 L/70)" was a 7.5 cm German tank gun developed and built by Rheinmetall-Borsig AG in Unterlüß during the Second World War. The gun was used to equip the SdKfz.171 Panther medium tank and the SdKfz.162/1 Jagdpanzer IV/70(A)/(V) tank destroyers. When mounted on a tank destroyer it was designated as the 7.5 cm PaK 42 "(7.5 cm Panzerabwehrkanone 42)".

The key feature of the weapon was its astounding muzzle velocity that enabled phenomenal accuracy and remarkable penetration capabilities. When the 7.5 cm KwK 42 entered service with the Panther in 1943 it could penetrate more armor than any of the enemy's antitank or tank guns. In this respect it was in fact even more powerful than the Tiger's famous 8.8 cm KwK 36 L/56 when using APCBC-HE rounds, though not with the APCR variety. With either ammunition type, the 7.5 cm KwK 42 performed less favorably than the 8.8 cm KwK 36 L/56 as range increased, due to the faster loss of velocity imparted on the lighter projectile by air drag. Also, being of a smaller calibre, it fired a weaker HE shell.

The gun was fired electrically, meaning that the primer was initiated using electric current rather than a firing pin. The breech operated semi-automatically so that after the gun had fired the empty shell casing was automatically ejected and the falling wedge type breech block remained down so that the next round could be loaded. When the round was loaded the breech closed automatically and the weapon was ready to be fired again. Three different types of ammunition were used: APCBC-HE, APCR and HE. The ammunition was fixed.

Following World War 2, a modified version of the gun remained in production in France as CN-75-50, which was mounted on AMX-13 light armored vehicle and Israeli M50 Super Sherman, a modified M4 Sherman tank with a redesigned turret to accommodate the gun.

Data for KwK 42 and Pak 42

*Type: Tank gun (KwK 42), Anti-tank gun (Pak 42)
*Caliber: 7.5 cm
*Barrel length in calibers: 70
*Barrel length in mm: 5250
*Breech: semiautomatic, falling wedge
*Weight with muzzle brake and breech: 1000 kg
*Recoil length: 400 mm (normal), 430 mm (maximum)
*Maximum range: 10 km (indirect)
*Sight: TZF 12 or 12a (Panther), Sfl.ZF 1a (Jagdpanzer IV/70 (A) and (V))

Ammunition data

APCBC-HE

**Designation: Panzergranate 39/42 (Pzgr. 39/42)
**Type: Armor Piercing Capped Ballistic Cap High Explosive
**Projectile weight: 6.8 kg
**Explosive filler: 18 g of phlegmatized RDX
**Round weight: 14.3 kg
**Round length: 893.2 mm
**Cartridge case length: 640 mm
**Muzzle velocity: 925 m/s
**Penetration, Rolled homogenous steel armor plate at 90° and 30° angles from the horizontal
**0 m: 167/133 mm
**450 m: 149/121 mm
**900 m: 133/110 mm
**1350 m: 118/99 mm
**1850 m: 104/89 mm
**2300 m: 91/79 mm

APCR

**Panzergranate 40 (Hk) (Pzgr. 40/42)
**Type: Armor Piercing Composite Rigid, tungsten core
**Projectile weight: 4.75 kg
**Round weight: 11.55 kg
**Round length: 875.2 mm
**Cartridge case length: 640 mm
**Muzzle velocity: 1120 m/s
**Penetration, Rolled homogenous steel armor plate at 90° and 30° angles from the horizontal
**0 m: 230/197 mm
**450 m: 198/154 mm
**900 m: 170/123 mm
**1350 m: 145/99 mm
**1850 m: 122/80 mm
**2300 m: 103/65 mm

HE

**Sprenggranate 42 (Sprgr. 42)
**Type: High Explosive
**Projectile weight: 5.74 kg
**Round weight: 11.14 kg
**Round length: 929.2 mm
**Cartridge case length: 640 mm
**Muzzle velocity: 700 m/s

References

* Gander, Terry and Chamberlain, Peter. "Weapons of the Third Reich: An Encyclopedic Survey of All Small Arms, Artillery and Special Weapons of the German Land Forces 1939-1945". New York: Doubleday, 1979 ISBN 0-385-15090-3

* Hogg, Ian V. "German Artillery of World War Two". 2nd corrected edition. Mechanicsville, PA: Stackpole Books, 1997 ISBN 1-85367-480-X
* Penetration data extracted from a French DoD publication "Le Panther" Ministere de la Guerre, Section Technique de l'Armee, Groupement Auto-Chars, 1947".