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 used on German armoured fighting vehicles in the Second World War. The gun was the armament of the Panther medium tank and two variants of the Jagdpanzer IV self-propelled anti-tank gun. On the latter it was designated as the "7.5 cm Panzerabwehrkanone 42" (7.5 cm Pak 42) anti-tank gun.

7,5 cm KwK 42 (L/70)
7,5 cm Pak 42
The 7.5 cm KwK 42 L/70 on a Panther Ausf. A tank
Typetank gun
Place of originGermany
Service history
Used by Nazi Germany
WarsWorld War II
Production history
DesignerRheinmetall-Borsig AG
ManufacturerRheinmetall-Borsig AG
Unit cost12,000 Reichsmark
Produced1942-45
Specifications
Mass1,000 kg (2,204.6 lb)
Barrel length525 cm (17 ft 3 in) bore (70 calibres)
ShellFixed QF 75 × 640mm R
Shell weight7.2 kg (16 lb) armour-piercing (APCBC-HE) Pzgr 39/42
Calibre75 mm (2.95 in)
Elevation-8° to +20°
Rate of fire6 rounds per minute
Muzzle velocity935 m/s (3,070 ft/s)
Maximum firing range9,850 m (32,316 ft)

Design

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.[1]

The gun was fired electrically, the primer being 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.

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 calibres: 70
  • Barrel length: 5.250 m (17 ft 2.7 in)
  • Breech: semiautomatic, falling wedge
  • Weight with muzzle brake and breech: 1,000 kg (2,200 lb)
  • Recoil length: 400 mm (normal), 430 mm (maximum)
  • Maximum range: 10 km (6.2 mi) indirect
  • Sight: TZF 12 or 12a (Panther), Sfl.ZF 1a (Jagdpanzer IV/70 (A) and (V))

Ammunition
Panzergranate 39/42 (Pzgr. 39/42)
  • Type: Armour Piercing Capped Ballistic Cap, High Explosive
  • Projectile weight: 6.8 kg (15 lb)
  • Explosive filler: 18 g of phlegmatized RDX
  • Round weight: 14.3 kg (32 lb)
  • Round length: 893.2 mm (2 ft 11.17 in)
  • Cartridge case length: 640 mm (2 ft 1 in)
  • Muzzle velocity: 935 m/s (3,070 ft/s)
Penetration of an armoured plate 30 degrees from vertical[2]
Range 100 m 500 m 1000 m 1500 m 2000 m
Penetration (mm) 138 124 112 99 89
Panzergranate 40 (Hk) (Pzgr. 40/42)
  • Type: Armour Piercing, Composite Rigid
  • Projectile weight: 4.75 kg (10.5 lb)
  • Round weight: 11.55 kg (25.5 lb)
  • Round length: 875.2 mm (2 ft 10.46 in)
  • Cartridge case length: 640 mm (2 ft 1 in)
  • Muzzle velocity: 1,130 m/s (3,700 ft/s)
Penetration of an armoured plate 30 degrees from vertical[2]
Range 100 m 500 m 1000 m 1500 m 2000 m
Penetration (mm) 194 174 149 127 106
Sprenggranate 42 (Sprgr. 42)
  • Type: High explosive
  • Projectile weight: 5.74 kg (12.7 lb)
  • Explosive weight: 0.650 kg (1.66 lb) (2,720 Kilojoules)
  • Round weight: 11.14 kg (24.6 lb)
  • Round length: 929.2 mm (3 ft 0.58 in)
  • Cartridge case length: 640 mm (2 ft 1 in)
  • Muzzle velocity: 700 m/s (2,300 ft/s)

Penetration comparison
Calculated penetration (90 degrees) uses American and British 50% success criteria,
and allowing direct comparison to foreign gun performance.[3]
Ammunition typeMuzzle velocity
(m/s)		Penetration (mm)
100 m 250 m 500 m 750 m 1000 m 1250 m 1500 m 2000 m 2500 m 3000 m
Pzgr. 39/42 (APCBC) 935 m/s (3,070 ft/s) 185 179 168 158 149 140 132 116 103 91
Pzgr. 40/42 (APCR) 1,130 m/s (3,700 ft/s) 265 253 234 216 199 184 170 145 124 105

See also

Weapons of comparable role, performance and era

Notes
  1. US Army Technical Manual TM9-1985-3, United States Government Printing Office Washington, 1953
  2. Jentz, Thomas L. (1997), Germanys Panther Tank: The Quest for Combat Supremacy (Hardcover ed.), Schiffer Military History, p. 125
  3. Bird, Lorrin Rexford; Livingston, Robert D. (2001). WWII Ballistics: Armor and Gunnery. Overmatch Press. p. 61.

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.
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