Schwerer Gustav and Dora were the names of two German 80 cm K (E) ultra-heavy railway guns. They were developed in the late 1930s by Krupp as siege artillery for the explicit purpose of destroying the main forts of the French Maginot Line, the strongest fortifications then in existence. The twin guns weighed nearly 1,350 tonnes, and could fire shells weighing seven tonnes to a range of 47 kilometres (29 mi). The guns were designed in preparation for the Battle of France, but were not ready for action when the battle began, and in any case the Wehrmacht's Blitzkrieg offensive through Belgium rapidly outflanked and isolated the Maginot Line's World War I-era static defenses, forcing them to surrender uneventfully and making their destruction unnecessary.
Gustav was later used in the Soviet Union at the siege of Sevastopol during Operation Barbarossa, with good effect, including destroying a munitions depot buried in the bedrock under a bay. They were moved to Leningrad, and may have been intended to be used in the Warsaw Uprising like other German heavy siege pieces, but the rebellion was crushed before they could be prepared to fire. Gustav was later captured by US troops and cut up, whilst Dora was destroyed near the end of the war to avoid capture by the Red Army.
It was the largest-calibre rifled weapon ever used in combat, and fired the heaviest shells of any artillery piece. It is only surpassed in calibre by the British Mallet's Mortar and the American Little David mortar (both 36 inch; 914 mm)
n 1934 the German Army High Command (OKH) commissioned Krupp of Essen to design a gun to destroy the forts of the French Maginot Line which 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 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 enquired 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. 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 Rügenwald Proving Ground during the formal acceptance trials of the Gustav Gun in early 1941.
World War IIEdit
In February 1942, Heavy Artillery Unit (E) 672 reorganized and went on the march, and Schwerer Gustav began its long ride to the Crimea. The train carrying the gun was of 25 cars, a total length of 1.5 kilometres. The gun reached the Perekop Isthmus in early March 1942, where it was held until early April. A special railway spur line was built to the Simferopol-Sevastopol railway 16 kilometres (9.9 mi) north of the target, at the end of which four semi-circular tracks were built specially for the Gustav to traverse. Outer tracks were required for the cranes which assembled Gustav.
The siege of Sevastopol was the gun's first combat test. By the end of the siege on 4 July the city of Sevastopol lay in ruins, and 30,000 tons of artillery ammunition had been fired. Gustav had fired 48 rounds and worn out its original barrel, which had already fired around 250 rounds during testing and development. The gun was fitted with the spare barrel and the original was sent back to Krupp's factory in Essen for relining.
The gun was then dismantled and moved to the northern part of the eastern front, where an attack was planned on Leningrad. The gun was placed 30 km from the city near the railway station of Taizy. The gun was fully operational when the attack was cancelled. The gun then spent the winter of 1942/43 near Leningrad. The gun appears to have been destroyed to prevent its capture some time before 22 April 1945, when its ruins were discovered in a forest 15 kilometres (9.3 mi) north of Auerbach about 50 kilometres (31 mi) southwest of Chemnitz.