7.5 cm Pak 40

Development of the Pak 40 began after reports of new Soviet tank designs began to reach Berlin in 1939. The 5 cm Pak 38 was still in testing at this point, but it appeared it would not be powerful enough to deal with these newer designs. Contracts were placed with Krupp and Rheinmetall to develop what was essentially a 7.5 cm version of the Pak 38. However, while the Pak 38 made extensive use of light alloys to reduce overall gun weight, these were now earmarked for the Luftwaffe. As a result, the Pak 40 used steel throughout its construction and was proportionally heavier than the 5 cm model. To simplify production, the Pak 38's curved gun shield was replaced by one using three flat plates.[4] A version called the 7.5 cm FK 7M59 was proposed towards the end of the war to fill a dual-purpose role of field gun and anti-tank gun. The carriage was modified to provide +35° of elevation which increased maximum range to 13,300 m (14,500 yd).[5] Another dual purpose variant was the 7.5 cm FK 7M85 which used the gun and recoil system of the Pak 40 on the carriage of the 10 cm le FH 18/40.[5]

The project was initially given low priority, but following the invasion of the USSR in 1941 and the appearance of heavily armoured Soviet tanks such as the T-34 and KV-1, it was given an increased priority. The first pre-production guns were delivered in November 1941. In April 1942, the Wehrmacht had 44 guns in service; by 1943, the Pak 40 formed the bulk of German anti-tank artillery.

The Pak 40 was the standard German anti-tank gun until the end of the war, and was supplied by Germany to its allies. Some captured guns were used by the Red Army. After the war, the Pak 40 remained in service in several European armies, including Albania, Bulgaria, Czechoslovakia, Finland, Norway, Hungary and Romania.

A Finnish army Pak 40 in firing position during the Continuation War

23,303 Pak 40s were produced, and about 3,500 more were used to arm tank destroyers. The unit manufacturing cost amounted to 2,200 man-hours at 12,000 RM. A lighter automatic "weapon system" version incorporating a twelve-round magazine, the heaviest of the Bordkanone series of heavy calibre aircraft guns, was used as the BK 7,5 in the Henschel Hs 129B-3 and the Junkers Ju 88P-1 ground attack aircraft, and even intended as a production fitment for a possible He 177A-3/R5 heavy bomber adaptation late in 1942, originally prototyped in the field with BK 5 cannons, themselves adapted from the 5 cm KwK 39 tank gun from the Panzer III.

During the second half of World War II, some Romanian anti-tank platoons each had three Pak 40 guns. These were used interchangeably with Romania's own 75 mm Reșița Model 1943 anti-tank gun.[6]

7,5 cm Pak 40 in Albania in 1943

The weapon was effective against almost every Allied tank until the end of the war, only struggling to penetrate heavier vehicles like the Russian IS tanks, the American M4A3E2 Sherman 'Jumbo' and M26 Pershing, and later variants of the British Churchill tank. The Pak 40 was much heavier than the Pak 38; its decreased mobility meant that it was difficult or even impossible to move without an artillery tractor on boggy ground.

The Pak 40 was first used in the USSR where it was needed to combat the newest Soviet tanks. It was designed to fire the same low-capacity APCBC, HE and HL projectiles that had been standardized for use in the long barrelled Kampfwagenkanone KwK 40 tank-mounted guns of the mid-war and later marks of the Panzer IV medium tank. In addition, there was an APCR shot (Panzergranate 40) for the Pak 40, a munition which - reliant on supplies of tungsten - eventually became very scarce.[7] According to the German Panzertruppen News Journal, 5,000 APCR rounds were expected in Dec. 1942 as replenishment for the Winter offensive.[8]

The main differences amongst the rounds fired by 75 mm German guns were in the length and shape of the cartridge cases as well as the primers used. The 7.5 cm KwK 40 (75x495mm) used in tanks had a fixed cartridge case twice the length of that used by the 7.5 cm KwK 37, the short barrelled 75 mm used on earlier tanks, and the 7.5 cm Pak 40 cartridge was a third longer than that used by the KwK 40. The Pak 40 used a percussion primer, while the vehicle mounted 75 mm guns used electrical primers. Other than minor differences with the projectiles' driving bands, all German 75 mm guns used the same 75mm projectiles.

German Panzerjäger use a Pak 40 against Yugoslav partisans in Bosnia on 12 January 1944.

The longer cartridge case of the Pak 40 allowed a larger charge to be used and a higher velocity for the PzGr 39 armour-piercing capped ballistic cap round to be achieved. The muzzle velocity was about 790 m/s (2,600 ft/s) as opposed to 740 m/s (2,400 ft/s) for the KwK 40 L/43 and 750 m/s (2,500 ft/s) for the L/48. The only 75mm fighting vehicle gun in general use by Germany that possessed a longer barrel than the Pak 40, the 7.5 cm KwK 42 on the Panther tank, could achieve a higher muzzle velocity of 935 m/s (3,070 ft/s) on what was essentially the same calibre and model of shell, with a differing propellant cartridge fixed to it for the KwK 42's use.

For unknown reasons, some 75 mm APCBC cartridges appear to have been produced with a charge that gave a muzzle velocity of about 770 m/s (2,500 ft/s). The first documented firing by the US of a Pak 40 recorded an average muzzle velocity of 776 m/s for its nine most instrumented firings.[9] Probably because of these results, period intelligence publications ("Handbook on German Military Forces") gave about 770 m/s as the Pak 40 APCBC muzzle velocity. Post war publications corrected this.[10]

German sources differ; the Official Firing Table document for the 75 mm KwK 40, StuK 40 and the Pak 40 dated October, 1943, gives 770 m/s on one of the APCBC tables.[11]

Detailed view of the cannon breech.

German Pak 40 75 mm

Pak 40 seen from the rear

• Caliber: 75 mm
• Barrel length: L/46
• Rifling: 32 grooves, right-hand increasing twist, 1/24 to 1/18.
• Length with the carriage: 6.2 metres (20 ft 4 in)
• Length: 3.70 metres (12 ft 1.7 in)
• Width: 2.0 metres (6 ft 7 in)
• Height: 1.25 metres (4 ft 1 in)
• Weight (combat ready): 1,425 kilograms (3,142 lb)
• Traverse: 65°
• Elevation: -5° to + 22°
• Rate of fire: 14 rounds per minute
• Engagement range: 1,800 metres (5,906 ft)
• Indirect range: 7,678 metres (25,190 ft) (HE shell)
• Projectile weight: 3.18 to 6.8 kg (7 lb 0.2 oz to 14 lb 15.9 oz)

Panzergranate 39 (PzGr. 39)

An armour-piercing, capped, ballistic cap (APCBC) projectile with explosive filler and tracer.

• Weight of projectile: 6.80 kg (15 lb 0 oz)
• Muzzle velocity: 790 m/s

Panzergranate 40 (PzGr. 40)

An armour-piercing, composite rigid (APCR) projectile with a sub-calibre tungsten core.

• Weight of projectile: 4.05 kg (8 lb 15 oz)
• Muzzle velocity: 990 m/s

Panzergranate 38 HL/B (PzGr. 38 HL/B)

A high-explosive anti-tank (HEAT) projectile with a shaped charge.

• Weight of projectile: 4.57 kg
• Muzzle velocity: 450 m/s

After the war, the gun was used by the Norwegian Army. In 1955, USSR supplied 33 captured guns to Austria. They were kept in service into the 1960s.[13] North Vietnam also received some during the Vietnam War.[14]

Pak 40s are or have been held in several military museums, outside museums or free entrance open-air fields:

Country	Place	Location
Belgium	Atlantic Wall Open Air Museum, Raversijde	Ostend
Brazil	Museu do Expedicionário	Curitiba, Brazil
Canada	Base Borden Military Museum	Borden, Ontario
Canada	The Central Museum of The Royal Regiment of Canadian Artillery	Shilo, Manitoba
Denmark	Danish War Museum	Copenhagen
Finland	Salpa Line Museum	Miehikkälä, South Karelia
Finland	Bunker Museum	Virolahti, South Karelia
Finland	Parola Tank Museum	Parola, Western Finland Province
Finland	Infantry Museum	Mikkeli, Southern Savonia
Finland	Northern Brigade (Pohjan prikaati) memorial area, 2 pieces	Oulu, Northern Ostrobothnia
Finland	Cannons at Torp, museum	Ingå, Uusimaa
Finland	The Artillery Museum of Finland	Hämeenlinna, Tavastia Proper
Finland	Hanko Front Line Museum[15]	Hanko, Uusimaa
Finland	Military Museum of Finland, Suomenlinna filial	Helsinki
France	Musée Mémorial Bataille de Normandie	Bayeux
France	Musée des Blindés or Association des Amis du Musée des Blindés[16]	Saumur
France	Centre village	Le Dézert
Germany	Deutsches Panzermuseum	Munster
Netherlands	Atlantikwall-Museum	Hook of Holland
Netherlands	Centre village green	Zandoerle
Romania	Oarba de Mures heroes monument, 2 pieces in open air	between Sfantu Gheorghe and Oarba de Mures villages, on road 120, Mures county
Romania	National Military Museum, Romania, 1 piece	Bucharest
Romania	Military Museum, 1 piece	Dej
Serbia	Belgrade Military Museum	Belgrad
Spain	Museo de Unidades Acorazadas, and others	El Goloso, Madrid
Spain	Museo Histórico Militar de Canarias	Centro de Historia y Cultura Militar de Canarias, Santa Cruz de Tenerife
Spain	Museo Histórico Militar de Cartagena	Cartagena, Murcia
Syria	Military Museum, 2 pieces[17]	Damascus
USA	American Armoured Foundation Tank Museum	Danville, Virginia
USA	Privately owned collection	Tooele, Utah
USA	American Heritage Museum	Stow, Massachusetts
USA	VFW[18]	Collingswood, New Jersey
USA	American Legion	2179 Whiteford Rd Whiteford, Maryland
USA	Privately Owned Collection[19]	Uvalde, TX
USA	US Army National Guard armory	Memorial Parkway Utica, NY
UK	Imperial War Museum Duxford[20]	Duxford
Ukraine	Great Patriotic War Museum	Kiev

• 7.5 cm Pak 97/38 - captured French 75 mm anti-tank gun on German carriage
• 7.5 cm Pak 41 - 75 mm anti-tank gun based on squeeze bore principle
• 7.5 cm Pak 50 - A shortened L/30 version of Pak 40
• 7.5 cm KwK 40 - German tank gun version of Pak 40
• 7.5 cm FK 7M85 - A field gun based on the Pak40

Notes

Bibliography

• Engelmann, Joachim and Scheibert, Horst. Deutsche Artillerie 1934-1945: Eine Dokumentation in Text, Skizzen und Bildern: Ausrüstung, Gliederung, Ausbildung, Führung, Einsatz. Limburg/Lahn, Germany: C. A. Starke, 1974
• Wolfgang Fleischer. Die 7,5-cm Panzerjägerkanone 40 // Waffen-Arsenal Sonderband S-54. — PODZUN-PALLAS-VERLAG, 1999. — 52 p. — ISBN 3-7909-0665-4.
• Werner Haupt. Panzerabwehrgeschütze 3,7-cm 5,0-cm 7,5-cm 8,8-cm-Pak 1934-1945 (ohne Selbstfahrlafetten) // Waffen-Arsenal Band 117, PODZUN-PALLAS-VERLAG. — 1989. — ISBN 3-7909-0360-4.
• 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
• H.Dv. 481/77 Merkblatt fur die Munition der 7,5 cm Panzerjägerkanone 40 (7,5 cm Pak. 40), OKH Berlin 1942.
• D 393/1 7,5cm Panzerjägerkanone 40.- Heft 1: Beschreibung, Bedienung und Behandlung. — OKH / Heereswaffenamt, Berlin 1.Apr.1942.
• H.Dv. 119/324 – Schußtafel für die 7,5 cm Kampfwagenkanone 40 (7,5 cm Kw.K. 40), 7,5 cm Sturmkanone 40 (7,5 cm Stu.k. 40) und 7,5 cm Panzerjägerkanone 40 (7,5 cm Pak 40) mit Deckblättern 1-17, Oktober 1943.

Wikimedia Commons has media related to: PaK 40 (category)

• Intelligence report on Pak 40 at Lonesentry.com
• Technical information at Panzerworld
• Model Book German 7,5 cm Anti-tank Gun Pak 40