Pak 40

7.5 cm Panzerabwehrkanone 40
A Pak 40 75 mm anti-tank gun, displayed in Parola Tank Museum, Finland
Type	Anti-tank gun
Place of origin	Nazi Germany
Service history
In service	1942–1945
Used by	Nazi Germany Finland Kingdom of Hungary Norway (postwar)
Wars	World War II
Production history
Designer	Rheinmetall
Designed	1939–1940
Manufacturer	Rheinmetall
Produced	1942–1945
No. built	Approx. 20,000
Specifications
Weight	1,425 kg (3,142 lb) in action
Length	6.2 m (20 ft 4 in)
Barrel length	46 calibres: 3.45 m (11 ft 4 in)
Shell	75×714mmR
Caliber	75 mm (2.95 inch)
Breech	semi-automatic horizontal sliding block
Carriage	split trail
Elevation	-5° to +22°
Traverse	65°
Rate of fire	14 rounds per minute
Effective firing range	1,800 metres (5,906 ft) direct fire 7,678 metres (25,190 ft) indirect HE shell

The 7.5 cm Pak 40 (7,5 cm Panzerabwehrkanone 40) was a German 75 millimetre anti-tank gun developed in 1939-1941 by Rheinmetall and used during the Second World War. The Pak 40 formed the backbone of German anti-tank guns for the latter part of World War II, mostly in towed form, but also on a number of tank destroyers such as the Marder series. Approximately 20,000 Pak 40s were produced.

A modified version of the gun designed specifically for vehicle-mounting was the 7.5 cm KwK 40, which differed primarily in using more compact ammunition, thereby allowing more rounds to be carried inside the vehicles. The KwK 40 armed many of the German mid-war tank and destroyer designs, replacing the Pak 40 in the later role.

Depending on the source, the Pak 40 may be referred to as the 7.5/L46, referring to the barrel's length in calibres. There were two versions of the KwK 40, which would be referred to as the 7.5/L43 or 7.5/L48.

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 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.

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.