Paris Gun: World War One’s Greatest Weapon

At quarter past seven on the morning of March 23, 1918, the people of Paris were jolted by a powerful explosion near the Quai de la Seine. Fifteen minutes later, another blast echoed from Rue Charles V, followed by a third on Boulevard de Strasbourg near Gare de l'Est. The explosions continued throughout the day bringing life in the city to a standstill. Stores closed down and the Metro system stopped running. A great number of people came out into the streets with their eyes towards the sky as they tried to locate the planes that were supposedly dropping bombs on them.

The gun that bombed Paris from 120 km away. Photo credit: Wikimedia Commons

Europe was in the grip of war, and Paris was a key target for German forces. Since January 1918, the city had endured relentless nighttime bombings, primarily from aircraft and zeppelins. So when bombs began exploding in broad daylight, the initial assumption was that a new type of high-altitude aircraft—too high to be seen—was responsible. However, within a few hours sufficient fragments of the bomb casings were recovered to reveal that the explosions were not caused by bombs dropped from an airplane but by shells fired from a gun.

The absence of sound of artillery fire suggested that the shells must have originated from a great distance. In the days that followed, several intriguing theories surfaced in various newspapers. One idea proposed that the projectiles reaching Paris were fired from a much larger "flying gun." This larger projectile, it was suggested, had been launched from a distant gun, and once it reached a certain altitude, an internal charge would ignite, firing a smaller projectile that would eventually land in the city.

A simpler theory speculated that the shells were being fired from just behind German lines, perhaps from hidden locations in abandoned quarries or heavily wooded areas near Paris. Despite a thorough search of the forests surrounding the city, no such gun was discovered. Another possibility considered was that the shells were being fired from within Paris itself, using a pneumatic gun, which could explain the absence of the usual sound of firing.

It took several days since bombing commenced for the French to uncover the full extent of the weapon’s range and capabilities. The artillery responsible, now known as the "Paris Gun," was one of the most formidable weapons devised during World War I, capable of launching shells from an astonishing distance.

The Paris Gun

The Paris Gun was designed by Fritz Rausenberger, an engineer from the German arms manufacturer Krupp. Rausenberger had been developing long-range artillery for some time when he presented the German High Command with a bold proposal: an ultra-long-range gun capable of firing shells over 100 kilometers. The proposal received swift approval from Field Marshal Paul von Hindenburg, Chief of the General Staff, and his deputy, General Erich Ludendorff. Within a year, Rausenberger had created a working prototype, which successfully fired for the first time on November 20, 1917. After further testing with various propellant and projectile combinations, Krupp engineers managed to extend the gun's range to 125 kilometers—far surpassing anything that had been built before.

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Production of the Paris Gun began immediately. A total of seven barrels were prepared, each crafted from a repurposed 38 cm "Long Max" naval gun. To achieve the desired specifications, the barrels were fitted with an internal lining tube, reducing the caliber from 380 mm to 210 mm. This lining tube measured 102 feet in length and extended 46 feet beyond the original gun's muzzle. An extension was bolted onto the muzzle to enclose and reinforce the tube. Additionally, the rifled barrel was extended by another 20 feet with a smooth-bore attachment, resulting in a total barrel length of 121 feet. The gun’s sheer size and weight required an external truss system to be clamped along the barrel to prevent it from sagging under its own weight.

The Paris Gun prepared for rail transport. Photo credit: Wikimedia Commons

The guns were installed on the Mont-de-Joie north of Crépy-en-Laon, at three shooting locations 120 kilometers from Paris. The guns were pointed not exactly towards Paris, but slightly to the left to offset the drift the shells underwent as the Earth turned beneath. At a firing angle of 50 degrees, the shells soared into the stratosphere reaching a peak altitude of 40 kilometer—an altitude record that stood for nearly 25 years until the Germans tested the first V-2 missiles in 1942. At that altitude, reduced air resistance greatly increased horizontal range.

The extreme range necessitated very high velocities that caused enormous wear on the barrel, so much that with each successive shot a considerable amount of steel was worn away from the rifled bore. Each shell was, therefore, manufactured in gradually increasing diameters to match the rate of wear. The shells were sequentially numbered and had to be fired in exact order, failing which a shell could get stuck in the barrel and explode prematurely. Such an incident occurred in March 25, destroying Gun No.3 and killing several soldiers.

Trajectory of the shells fired from the Paris Gun.

After 60 rounds, the barrel was sent back to Krupp's factory in Essen to be re-bored to a diameter of 224 mm, after which a new set of shells was issued. Once another 60 rounds were fired, the barrels were re-bored a second time, this time to 238 mm.

Although the Paris Gun had an incredible range, and despite all the hassles of operating it, it was not a very effective weapon. The average projectile weighed 106 kilograms, but much of that weight was in the body of the shell, which had to be heavily reinforced to withstand the immense firing pressures. As a result, the explosive charge it carried was only 7 kilograms—far too small to produce a significant bang. One shell that landed in the Jardin des Tuileries, a famous park in Paris, left a crater only 10 to 12 feet wide and 4 feet deep. Even when shells struck buildings and exploded inside, the exterior often showed little to no visible damage.

A report prepared by the United States Army in 1921 noted the weapon’s underwhelming impact: “The visible destruction of property was so slight as to give little evidence to anybody traveling about the city that the explosions they were hearing from time to time amounted to anything.”

Map of Paris, showing where shells fired by the Paris Gun landed, June-August 1918. The black line across the map indicates the direction from which the shells arrived. Image credit: Wikimedia Commons

The Paris Gun's immense range had a major drawback—it was grossly inaccurate. The gun could not aim at anything smaller than an entire city, and even within Paris, the shells landed all over without hitting anything substantial. Between March and August, the three Paris Guns fired approximately 367 rounds (though French records report 303), but only 183 of those shells landed within the city limits. The shells killed 250 people and injured 620, with the deadliest incident occurring on March 29, 1918, when a shell struck the roof of St-Gervais-et-St-Protais Church, killing 91 worshippers and wounding 68 when the roof collapsed.

The Paris Gun fired its last round on the afternoon of August 9, 1918, after which it was withdrawn to Germany as advancing Allied forces began to threaten its position. By the war's end, the guns had been completely dismantled, and Krupp destroyed most of the research and development records related to the project. Today, the only physical evidence of the Paris Gun’s existence are the concrete firing emplacements that remain in the woods near Crépy.