The Nazis’ Schwerer Gustav, The Biggest Gun Ever Built

Published May 18, 2018
Updated February 8, 2024

The monstrous Schwerer Gustav was deployed in the Soviet Union during the Battle of Sevastopol.

Hitler Inspecting Schwerer Gustav Railway Gun

Wikimedia CommonsAdolf Hitler and other SS officers inspect the Schwerer Gustav.

One thing stood before the Nazis — literally — as they prepared to launch war on Europe: France’s Maginot Line. Built in the 1930s, the defensive line stretched almost 300 miles long and included fortresses, gun batteries, bunkers, and minefields. To penetrate it, the Nazis developed a wunderwaffe (“miracle weapon”) called Schwerer Gustav.

This gargantuan railway gun weighed 1,350 tons and could fire seven ton shells at targets almost 30 miles away. It probably could have torn the Maginot Line to shreds — if it had been finished in time. The fearsome weapon missed that deadline, but it was used later on in the war.

So what was the Schwerer Gustav, the towering railway gun that required 2,000 men to operate it? How was it used during World War II, and why did it disappear in the middle of the conflict?

The Development Of The Schwerer Gustav

By the 1930s, the concept of superweapons like the Schwerer Gustav had been around for a while. The Russians built the 39-ton Tsar Cannon in 1568, the British constructed the 42-ton Mallet’s Mortar in 1857, and the Germans unveiled the 47-ton “Big Bertha” in 1914. (Of these three enormous weapons, however, only Big Bertha was used during conflict.)

Soldier With Projectile

Public DomainA soldier with a projectile marked “Big Bertha” and with a skull and crossbones. 1918.

By the 1930s, the Nazis started dreaming up a similar weapon which they could use to break through France’s Maginot Line. The gun to do so was designed by Krupp, a steel company based in Essen. Adolf Hitler was interested in its development — he asked about it during a 1936 visit to the company — but developing the gun presented problems.

In order to break through the Maginot Line, the weapon’s shells would have to be powerful enough to break through 22 feet of reinforced concrete and at least three feet of steel plating. It would have to be, in other words, a gargantuan weapon unlike anything that had ever been built before.

But Krupp was up to the challenge. Though they missed the deadline to invade France (the Nazis ended up going around the Maginot Line, through Belgium, in May 1940) the Nazi’s new weapon was ready for testing by the end of 1941. It was called Schwerer Gustav, schwerer meaning “heavier” in German and Gustav being a nod to Krupp’s senior director, Gustav Krupp.

Schwerer Gustav: A Weapon Like No Other

By the time the Schwerer Gustav was complete at the end of 1941 — it cost 10 million marks to build — it was more like a small building than a gun. From the ground up the Schwerer Gustav was almost four stories tall. The weapon weighed 1,350 tons, and was 20 feet wide and a 140 feet long.

Schwerer Gustav On Tracks

Public DomainThe Schwerer Gustav had to be transported along railway tracks, which could make concealing its movements difficult.

It had a caliber of 31 inches, and was able to hit targets roughly 30 miles away. Its barrel alone was over 100 feet long and Popular Mechanics reports that it was able to fire two kinds of shells: a 10,584-pound high-explosive shell and a 16,540-pound concrete-piercing shell.

The Schwerer Gustav was so large, in fact, that it required hundreds of men to operate it. (Some sources say 500 men were needed; others claim that as many as 2,000.) It took several men to load just the gun’s enormous shells, and the weapon was so large that it could not travel in one piece.

World War II database explains that the gun was actually transported in five units: the breech ring and block, the barrel split in two halves, the barrel jacket, the cradle, and the trunnions.

Though some sources claim that the Schwerer Gustav was one of two such guns built, World War II database reports that this is untrue. They claim that this misconception comes from the German artillerymen who mockingly called the weapon “Dora,” leading to the belief that two guns (Schwerer Gustav and Dora) were built. In fact, they may have been one in the same.

And though Schwerer Gustav was not ready in time to breach the French defenses, it was used in battle during World War II.

How The Weapon Was Used During WWII

Though the Schwerer Gustav was not used to break the Maginot Line, the Nazis still wanted to test out their mighty new weapon. In mid-1942, a team of over 1,000 men took three weeks to assemble the mighty weapon. Then, it was off to join the siege of Sevastopol.

Between June and July, Schwerer Gustav rained down destruction on the besieged Soviet city. World War II database reports that it fired 50 of its shells, one of which purportedly smashed through 100 feet of earth before blowing up an underground Soviet ammunition store.

Sevastopol After The Siege

German Federal ArchivesSevastopol after the siege. July 1942.

By the end of the siege, Sevastopol lay in smoldering ruins. The Axis had won a decisive victory.

But the Schwerer Gustav was hardly ever used again.

The German Army transported the mighty weapon to Leningrad (present-day St. Petersburg) but the Soviet forces were able to repel the Germans before they could use their new wunderwaffe. In 1944, it was lugged to Poland and managed to fire 30 shells during the Warsaw Uprising.

After that, however, the powerful Nazi weapon vanished from the record.

Railway Gun

Public DomainA railway gun in Germany that appears to be the Schwerer Gustav.

It’s unclear exactly what happened to the Schwerer Gustav. It was most likely scrapped by the Nazis sometime in 1944. By then, the super weapon may have simply posed more problems than advantages.

A Weapon That Was Perhaps Too Powerful

Shell Casing From A Schwerer Gustav Gun

Wikimedia CommonsA single shell was taller than two men, and twice as wide as one.

Though the Schwerer Gustav could wreak destruction on its targets, it was, ultimately, an impractical weapon. It required incredible manpower to operate and during battle it was hard to spare so many soldiers.

Furthermore, it took the German Army multiple days just to move the giant railway gun. This was hard enough. Moving it covertly was next to impossible. The gun was huge and difficult to hide from planes, which meant that the Allies could track its movements unless the Luftwaffe had total air control.

Finally, maintenance and the cost of shells of the Schwerer Gustav was expensive, and hard to justify when there were smaller, more covert tanks readily available.

And so the Schwerer Gustav, the 10 Million mark Nazi dream, disappeared from the battlefield. This wunderwaffe ended up being less miraculous than the Nazis had hoped. Just three years after it was first deployed in Sevastopol, Germany unconditionally surrendered.


After learning about the Schwerer Gustav railway gun, check out these other crazy weapons invented by the Nazis. Then, read about the Landkreuzer P. 1500, a German tank so large it couldn’t even be built.

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