42cm kurze Marinekanon 12 /Gamma-Gerät

The 42cm kurze Marinekanon 12 or Gamma-Gerät  was a very heavy siege howitzer that was potentially very effective, but that took too long to prepare for use, and as a result was less effective than the slightly lighter but more mobile M-Gerät.

Before the First World War Krupp produced a series of heavy guns and howitzers, mainly designed to defeat the French and Belgian forts that had the potential to block the German right wing during any attempt to implement the Schlieffen Plan. This started with the 30.5cm schwere Küstenmörser L/8 or Beta-Gerät of the 1890s, and the 30.5cm schwerer Küstenmörser 09/ Beta-Gerät 09, but although these were effective weapons, it was clear that heavier guns would be needed to deal with the new generation of modern fortifications.

Work on the 42cm Gamma-Gerät began in 1906, alongside the Beta-Gerät 09. In many ways the Gamma was a scaled up version of the Beta. Both used the same basic structure - starting with a deep foundation, on which a box base plate was installed. The carriage and barrel were mounted on top of this base plate, and two crew platforms were attached to allow the crew to reach the barrel, which was several meters in the air. A sloped ammo lift was installed to allow the heavy shells to reach breech level. When the gun was horizontal it was four meters above ground level!

The Gamma had to be broken up into ten railcar loads to be transported, each between 20 and 25 metric tons. The railcars were arranged into the order they were needed on site - wood for the foundations; steel rails for the gantry crane needed to assemble the main gun, the crane itself, rear half of foundations, front half of foundations, base plate, carriage with turntable, cradle for barrel, the barrel itself and finally the lift and platforms. Before work could begin on the foundations, a standard gauge railway had to be laid to the site to allow the railcars to reach it. It took 24 hours to assemble the Gamma after the railway had been completed.

A total of ten Gammas were built. The prototype was ordered in 1910, a second in 1911 and three in 1912. After the outbreak of war another five were completed, along with 18 spare barrels.

The Gamma Gerät was a very accurate and very powerful gun. However Gamma was designed to be transported in bits by train, and then re-assembled quite slowly on site. The German army wanted something more mobile, and so work moved onto the M-Gerät, or 'Big Bertha', a road-moveable 42cm howitzer that had little in common with Gamma. Big Bertha played a major part in the events of 1914 but soon faded from view. In contrast Gamma survived to see service during the Second World War, when at least one was used as the siege of Sevastopol.

The first Gamma-Geräts to get into action were serving with the Sixth Army in Lorraine. On 25-27 August two mortars from KMK Battery 1 took part in the bombardment of Fort Manonviller, although one soon had to stop firing because of mechanical problems, and both took some time to get into action. The fort surrendered because it had become filled with gases and not because of any great damage done by the siege artillery.

The Gamma-Geräts were then moved to Maubeuge, where they opened fire on 7 September. Within a few hours they destroyed Forst Leveau, Heronfontaine and Cerfontaine, and by the end of the day the fortress surrendered, ended a ten day long siege.

Battery KMK 2 then took its Gamma-Geräts to Antwerp. The battery opened fire on 28 September, hitting Fort Wavre-Sainte-Catherine. The fort surrendered on 29 September after a powder magazine was destroyed by a Gamma-Gerät shell. The battery then switched its fire to Fort Koningshooikt, which surrendered within a day.

After the end of the siege of Antwerp the impact of the heavy guns began to fade. The battery moved to the Channel front, where it was used to bombard Nieuport, Dixmude and Ypres, although without much impact.

The Gamma-Gerät's debut on the Eastern Front was even less successful. In February 1915 KMK Battery 1 took part in the five day siege of Osowiec, which was abandoned after only five days.

Three Gamma-Geräts, two M-Geräts and four Beta-Geräts took part in the successful siege of Kovno in August 1915.

Four Gamma-Geräts took part in the German invasion of Serbia in 1915, bombarding Serbian strong points.

Five Gamma-Geräts took part in the battle of Verdun, but although they were still effective against the strong concrete fortifications, they didn't have the same impact as in 1914. The modern French forts around Verdun proved able to stand up to 42cm fire. Three Gamma-Geräts were also destroyed when a shell detonated prematurely. 

One Gamma-Gerät survived the First World War. It was disassembled at the Krupp Proving Ground and hidden. It was rebuild in the late 1930s, and used in the Second World War. It was used against Liege and the Maginot Line in 1940, and during the siege of Sevastopol in 1942. It was then sent to bombard Kronstadt, but never opened fire. After that it disappeared.


42cm kurze Marinekanon 12



Barrel Length

6,700mm (L/16)

Weight for transport


Weight in action

42,000kg (excluding foundations)


43-66 degrees


45 degrees

Shell Weight


Muzzle Velocity


Maximum Range


Rate of Fire

1 round every five minutes

German Artillery 1914-1918, Wolfgang Fleischer. Covers over 100 guns used by the German Army and shore detachments of the Navy during the First World War, a conflict largely dominated by artillery. Each one gets a brief description, a set of technical stats and a good picture. Shows the wide range of gun types and sizes used by the Germans during the First World War, and the way in which they evolved to deal with the unexpected challenges of trench warfare. [read full review]
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Books on the First World War | Subject Index: First World War

How to cite this article: Rickard, J (28 November 2017), 42cm kurze Marinekanon 12 /Gamma-Gerät , http://www.historyofwar.org/articles/weapons_42cm_gamma_gerat.html

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