7.5 cm KwK 42

As mounted on Panther tank

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 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 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.

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: 1,000 kg (2,200 lb)
• 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 (16 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 figures given for an armoured plate 30 degrees from vertical^[2]

Range	Penetration (mm)
	100 m	500 m	1000 m	1500 m	2000 m
	138	124	112	99	89

Panzergranate 40 (Hk) (Pzgr. 40/42)

• Type: Armor 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 figures given for an armoured plate 30 degrees from vertical^[3]

Range	Penetration (mm)
	100 m	500 m	1000 m	1500 m	2000 m
	194	174	149	127	106

Sprenggranate 42 (Sprgr. 42)

• Type: High Explosive
• Projectile weight: 5.74 kg (12.7 lb)
• 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: 1,130 m/s (3,700 ft/s)

Penetration comparison

Penetration figures (90 degrees) uses American and British 50% success criteria,
and allowing direct comparison to foreign gun performance.^[4]

Ammunition type	Muzzle 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

• British Ordnance QF 17 pounder
• US 76 mm gun M1

Notes

1. US Army Technical Manual TM9-1985-3, United States Government Printing Office Washington, 1953
2. Germanys Panther Tank: The Quest for Combat Supremacy by Thomas L. Jentz, Schiffer Military History Hardcover, 1997
3. Germanys Panther Tank: The Quest for Combat Supremacy by Thomas L. Jentz, Schiffer Military History Hardcover, 1997
4. 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.

External links