Schwerer Gustav: The World’s Biggest Gun Ever Built

 Hitler certainly had some grand ideas – from mass murdering the Jews and conquering Europe to rebuilding Berlin and evacuating the Mediterranean. Even when it was generally meant to show how great Nazi Germany was, the Führer and his generals liked to act in style. He also built the world's largest hotel, but the project had to be abandoned because of more pressing matters such as the invasion of France.

In the 1930s, France built a series of massive fortifications and barriers, called the Maginot Line, to protect the country from invasion from the east. These fortifications, with deep underground bunkers, state-of-the-art retractable turrets, infantry shelters, barricades, artillery and anti-tank guns, etc., were some of the strongest in existence at the time. Nothing in the arsenal of the German Wehrmacht was capable of penetrating this formidable defence. So Hitler turned to munitions manufacturer Krupp for a solution.

Krupp engineer Erich Müller calculated that to punch a hole in seven meters of reinforced concrete or a full meter steel armor plate, they would need a gun with larger dimensions. If the gun was to fire shells weighing 7 tons from a distance of more than 40 kilometers, beyond the range of French artillery, it had to have an internal diameter of more than 80 cm and a length of more than 30 meters. The gun would weigh over 1,300 tonnes and would have to be carried on a set of railway tracks. When these data were presented to Hitler, he approved them and construction of this massive weapon began in 1937.

The super gun was ready in a little more than two years. In early 1941 Alfred Krupp personally took Hitler to the Rügenwalde Proving Ground to watch test firings of the gun. Alfred Krupp named the gun Schwerer Gustav or "Heavy Gustav" after his father, Gustav Krupp.

Schwerer Gustav was an absolute weapon monster. Because it was so big and heavy that the gun could not be moved completely. Instead, the gun was broken into several pieces and transported in 25 freight cars to the deployment site, where it was assembled in place – a task that required 250 people about three days to complete. Laying the tracks and digging the embankments took weeks of work and required 2,500 to 4,000 people working around the clock to complete it.

It took a lot of effort to assemble the gun. Here the barrels are being lowered into the carrier using two gantry cranes.

The Schwerer Gustav ran on a set of parallel tracks which limited its mobility. Furthermore, the gun's barrel could only aim vertically. Horizontal aiming was locked to the direction of the tracks. This required laying the tracks in a curve so that whenever the horizontal aim needed to be changed, the entire gun would be moved along the curved tracks. Despite tremendous firepower, Schwerer Gustav had no means of protecting itself. This was provided by two flank battalions that protected the guns from possible air attack.

Despite all the time and money spent on the gun's construction, it saw little action on the battlefield and no action at all against the French for whom it was originally envisioned. Germany invaded France in 1940, even before the gun was ready. They did this simply by getting around the Maginot Line, rendering the complex set of defenses useless.

Schwerer Gustav was deployed to the Eastern Front in Sevastopol during the siege of Russia in 1942. It took 4,000 people five weeks to prepare the guns for firing. Over the next four weeks, Gustav fired 48 rounds destroying distant forts and destroying an ammunition magazine located 30 meters below the seabed with at least 10 meters of concrete protection. The guns were then moved to Leningrad but the attack was cancelled.

Krupp made another gun with similar dimensions. It was named Dora after the wife of the company's chief engineer.

Dora was established west of Stalingrad in mid-August 1942, but was quickly withdrawn in September to avoid capture. When the Germans began the long retreat home they took Dora and Gustav with them. In 1945, with defeat imminent, the Germans blew up both Dora and Gustav to prevent the attacking Allied forces from capturing them, thus ending the story of the great Nazi supergun.

In terms of caliber, the Gustav and Dora were surpassed only by two other guns – the British Mallet mortar (created in 1857) and the American Little David (created during World War II), both of which are 914 mm. But only Gustav saw action on the battlefield. It is the largest gun ever deployed in combat – a record that is likely to stand indefinitely, as modern missiles and precision bombing have made the need for larger guns like the Gustav and David redundant.