"In 1934, the German Army High Command (OKH) commissioned Krupp of Essen to design a gun to destroy the forts of the French Maginot Line that were nearing completion. The gun's shells had to punch through seven metres of reinforced concrete or one full metre of steel armour plate, from beyond the range of French artillery. Krupp engineer Erich Müller calculated that the task would require a weapon with a calibre of around 80 cm, firing a projectile weighing 7 tonnes from a barrel 30 metres long. The weapon would have a weight of over 1000 tonnes. The size and weight meant that to be at all movable it would need to be supported on twin sets of railway tracks. In common with smaller railway guns, the only barrel movement on the mount itself would be elevation, traverse being managed by moving the weapon along a curved section of what turned out to be a dual-track railway line. Krupp prepared plans for calibres of 70 cm, 80 cm, 85 cm, and 1 m.

Nothing further happened until March 1936 when, during a visit to Essen, Adolf Hitler inquired as to the giant guns' feasibility. No definite commitment was given by Hitler, but design work began on an 80 cm model. The resulting plans were completed in early 1937 and approved. Fabrication of the first gun started in mid-1937. Technical complications in the forging of such massive pieces of steel made it apparent that the original completion date of early 1940 could not be met.

Krupp built a test model in late 1939 and sent it to the Hillersleben firing range for testing. Penetration was tested on this occasion. Firing at high elevation, the 7.1 tonne shell was able to penetrate the specified seven metres of concrete and the one metre armour plate.[5] When the tests were completed in mid-1940 the complex carriage was further developed. Alfried Krupp, after whose father the gun was named, personally hosted Hitler at the Rügenwalde Proving Ground during the formal acceptance trials of the Gustav Gun in early 1941.


An 800 mm Schwerer Gustav shell at the Imperial War Museum, London
Two guns were ordered. The first round was test-fired from the commissioned gun barrel on 10 September 1941 from a makeshift gun carriage on the Hillersleben firing range. In November 1941, the barrel was taken to Rügenwalde, now Darłowo, Poland, where eight further firing tests were carried out using the 7,100 kilogram armour-piercing (AP) shell out to a range of 37,210 metres.

In combat, the gun was mounted on a specially designed chassis, supported by eight bogies on two parallel sets of railway tracks. Each of the bogies had 5 axles, giving a total of 40 axles (80 wheels). Krupp christened the gun Schwerer Gustav (Heavy Gustav) after the senior director of the firm, Gustav Krupp von Bohlen und Halbach.

The gun could fire a heavy concrete-piercing shell and a lighter high-explosive shell. An extremely-long-range rocket projectile was also planned with a range of 150 km, that would require the barrel being extended to 84 metres.

In keeping with the tradition of the Krupp company, no payment was asked for the first gun.[citation needed] They charged seven million Reichsmark for the second gun Dora, named after the senior engineer's wife.


Weight 1,350 tonnes (1,490 short tons; 1,330 long tons)
Length 47.3 metres (155 ft 2 in)
Barrel length 32.5 metres (106 ft 8 in) L/40.6
Width 7.1 metres (23 ft 4 in)
Height 11.6 metres (38 ft 1 in)
Crew 250 to assemble the gun in 3 days (54 hours), 2,500 to lay track and dig embankments. 2 Flak battalions to protect the gun from air attack.
Caliber 80 centimetres (31 in)
Elevation Max of 48°
Rate of fire 1 round every 30 to 45 minutes or typically 14 rounds a day
Muzzle velocity 820 m/s (2,700 ft/s) (HE)
720 m/s (2,400 ft/s) (AP)
Effective firing range about 39,000 metres (43,000 yd)
Maximum firing range 47,000 metres (51,000 yd) (HE)
38,000 metres (42,000 yd) (AP)"