Largest-Calibre Rifled Weapon——Schwerer Gustav

Schwerer Gustav (English: Heavy Gustaf, or Great Gustaf) and Dora were the names of two German 80 cm K (E) 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 fully assembled 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 employed in the Soviet Union at the siege of Sevastopol during Operation Barbarossa, where among other things, it destroyed a munitions depot buried in the bedrock under a bay. The guns 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 in 1945 to avoid capture by the Red Army.

Dora's shell

 

It was the largest-calibre rifled weapon ever used in combat, the heaviest mobile artillery piece ever built in terms of overall weight, 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).