- Years of issue – 1941 – 1945
- In total, 23303 units were produced.
- Caliber – 75 mm
- Weight in firing position – 1425 kg
- Barrel length – 3450 mm
- The length of the threaded part – 2470 mm
- Calculation – 8 people
- Travel speed – 40 km / h
- Rate of fire – 12 – 15 rds / min
- The greatest firing range – 10,000 m
- Direct shot range – 900 m
- Shooting angles:
- Horizontal – 65 °
- Vertical – 6 ° + 22 °
In 1938, when the military tests of the 50-mm anti-tank gun Rak.38 were still being carried out, the Wehrmacht high command OKN formulated a new tactical and technical task for a heavy 75-mm anti-tank gun, which could withstand promising tanks with anti-cannon armor from all potential opponents. Third Reich. Concern Rheinmetall-Borsig AG, in the same year, began to design a 75-mm anti-tank gun.
The first version of the new gun was an enlarged Rak 38 cannon. But its tests, carried out in 1939, revealed a number of serious design flaws: aluminum assemblies, widely used in a 50-mm gun carriage, and, above all, tubular-type beds, could not stand up sharply increased loads. It took a redesign of the gun, but the work was carried out at a slow pace, since the Wehrmacht did not feel the need for an anti-tank gun more powerful than the Rak 38.
The impetus to accelerate the creation of the 75-mm gun was given by news from the Eastern Front, and first of all, the appearance of the Soviet T-34 and KV tanks. Taking into account the lessons of the first year of the war with the Soviet Union, the German command took a number of measures to strengthen its anti-tank artillery: the creation of more powerful anti-tank guns, as well as the widespread use of guns belonging to the countries occupied by Germany in the Wehrmacht.Thus, the development of German anti-tank artillery went along the line of increasing the armor-piercing effect of shells by increasing the caliber and initial speeds as a result of changes in the design of the guns and the use of special ammunition – sub-caliber shells. In addition, the Germans sought to increase the speed of movement of anti-tank guns, which was reflected in the design of the chassis (the introduction of suspension and pneumatic brakes controlled by the tractor driver), as well as to increase the maneuverability of anti-tank guns on the battlefield, for which a number of self-propelled units were created.As part of these measures, the Rheinmetall-Borsig company urgently completed the development of the Cancer 40. Already in December 1941, the first prototypes of the gun were tested, and in January 1942, the Wehrmacht adopted a new cannon under the designation 7.5-cm Panzerabwehrkanone 40 ( Rak.40) “(75-mm anti-tank gun sample 40). At the same time, its mass production began, and already in February of the same year, the first 15 Rak.40s entered the troops on the Eastern Front.
The main parts of the Rak.40 cannon were: a barrel with a bolt, a cradle with recoil devices, an upper machine, lifting, swivel and balancing mechanisms, a lower machine with undercarriages, a shield cover and sights. The monoblock barrel had a highly efficient double-chamber muzzle brake that absorbed a significant part of the recoil energy. The shutter is a semi-automatic horizontal wedge, opening during rollback, which provided a fairly high rate of fire of 12-15 rounds per minute. The carriage with sliding beds was equipped with torsion cushioning, which was automatically switched off when the beds were extended. Rollback brake – hydraulic, spindle type; knurler – hydropneumatic.
The gun had a pneumatic balancing mechanism of two columns and sector mechanisms for vertical and horizontal guidance, mounted on a cradle. The design of the shield cover was similar to that of the Rak-38 cannon and consisted of an upper shield of two armor plates, each 5 mm thick (with a distance between the sheets of 25 mm), mounted on the upper machine, and a lower shield, mounted on the lower machine and having a folding part …
The Rak.40 cannon was transported by means of mechanical traction. Wheels were produced from light alloy of two types – with solid discs with holes for lightening and with spokes. They had massive rubber tires and were equipped with pneumatic brakes controlled by the driver from the tractor cab. There was also a handbrake (levers on both sides of the carriage). To roll the gun by hand by means of calculation, the trunk of the gun was mounted on a roller (“steering wheel”) weighing 56 kg, while the gun was moved forward with the muzzle. One person guided the implement using a steering lever. The height of the line of fire was 960 mm.
The Rak.40 cannon ammunition consisted of unitary rounds with a high-explosive fragmentation grenade, armor-piercing, subcaliber armor-piercing, smoke and cumulative shells. The high-explosive fragmentation grenade (weighing 5.74 kg) was equipped with a head fuse of instantaneous and inertial action with deceleration. Its initial speed was 550 m / s, and the greatest firing range was 7700 m. The armor-piercing tracer projectile (weighing 6.8 kg) had a bottom deceleration fuse. Its initial speed was 770 m / s. Direct shot range 900 m (with a target height of 2 m). The actual firing range against tanks is 1500 m.
An armor-piercing tracer projectile with an armor-piercing core weighed 4.1 kg. There was also a sub-caliber armor-piercing tracer projectile, without an armor-piercing core, with an initial speed of 990 m / s. The direct shot range was 1100 m. Armor penetration at an angle of 60 ° was: at a distance of 500 m – an armor-piercing tracer projectile – 95 mm, a subcaliber armor-piercing tracer projectile – 120 mm; at a distance of 1000 m – 84 mm and 97 mm; at a distance of 1500 m – 75 mm and 77 mm (respectively).For firing at heavy tanks with especially powerful armor at short ranges (up to 600 m), three types of cumulative projectiles weighing (4.4 kg; 4.4 kg and 4.9 kg) were used, equipped with an instantaneous head fuse. At an encounter angle of 60 °, these projectiles pierced armor with a thickness of 75 to 90 mm (depending on the type of projectile), which made it possible to successfully use the Rak-40 cannon to combat a significant part of the armored vehicles of the USSR and its allies. The mass of a cartridge with a high-explosive fragmentation grenade was 9.1 kg, with an armor-piercing projectile – 11.9 kg, with a sub-caliber projectile – 8.8 kg, with a cumulative projectile – 7.5 kg.
The Rak.40 anti-tank guns were also in service with the tank destroyer divisions in the infantry divisions (36 units). The main purpose of the Rak.40 cannon was to combat enemy tanks and armored vehicles, however, a sufficiently large caliber and the presence of a high-explosive fragmentation projectile in its ammunition set made it possible to use this weapon to suppress firing points, destroy various light obstacles and to destroy enemy manpower.
The Rak.40 became the most successful and most massive anti-tank gun of the Wehrmacht during the Second World War. Not only the plants of the Rheinmetall-Borsig AG concern, but also the Ardeltwerke company (Eberswalde) were connected to its production; Gusloffwerke (Weimar) and Ostlandwerke (Konigsberg). The total production of the Rak.40 cannons in 1941-1945 amounted to 23,303 units, of which more than 3,000 were used in the Marder II, Marder III and Jagdpanther self-propelled guns. In addition, its carriage served as the basis for the creation of a modernized 105-mm light field howitzer sample 18/40 and 75 mm anti-tank gun Rak.97 / 40, which was the imposition of the barrel of a 75-mm French gun model 1897 on the carriage of the Rak.40 cannon.