7.5 cm KwK 42

The 7.5 cm KwK 42 L/70 (from 7.5 cm Kampfwagenkanone 42 L/70) was a 7.5 cm calibre 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 destroyer. When mounted on a tank destroyer it was designated as the 7.5 cm PaK 42 (7.5 cm Panzerabwehrkanone 42).

Design
The key feature of the weapon was its high muzzle velocity which enabled high accuracy and good penetration capabilities. When the 7.5 cm KwK 42 entered service with the Panther in 1943 it could penetrate more armor than any Soviet, American or British tank gun then in service. In this respect it was even more powerful than the Tiger's famous 8.8 cm KwK 36 L/56. The KwK 42 however fired a weaker HE shell.

The increased muzzle velocity and operating pressure of the new gun required a new armour piercing projectile to be designed. The PzGr. 39/42 was the result, and apart from the addition of wider driving bands it was otherwise identical to the older 7.5 cm Pzgr.39. The wider driving bands added a little extra weight, from 6.8 kg for the old PzGr.39, to 7.2 kg for the new PzGr.39/42.

The gun was fired electrically, the primer was initiated using an 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. Once 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 II, 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 (2.95 in)
 * Shell: 75×640 mm R
 * Barrel length in calibers: 70
 * Barrel length: 5.250 m (17 ft 2.69 in)
 * 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

 * Panzergranate 39/42 (Pzgr. 39/42)
 * Type: Armor Piercing Capped Ballistic Cap High Explosive
 * Projectile weight: 7.2 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 - 1000 m/s depending on source being used.
 * Average penetration performance established against rolled homogenous steel armor plate laid back at 30° from the vertical


 * 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
 * Average penetration performance established against rolled homogenous steel armor plate laid back at 30° from the vertical
 * 100 m: 194 mm
 * 500 m: 174 mm
 * 1000 m: 149 mm
 * 1500 m: 127 mm
 * 2000 m: 106 mm


 * 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