42cm Gamma-Gerät
AGamma-Gerät in 1914
Type	Siege artillery
Place of origin	German Empire
Service history
In service	1909–1942
Used by	German Empire Nazi Germany
Wars	World War I World War II
Production history
Manufacturer	Krupp
No. built	10
Specifications
Mass	150 t (150 long tons)
Length	13.5 m (44 ft)
Barrel length	6.7 m (22 ft) L/16
Height	4.25 m (13.9 ft)
Diameter	420 mm (17 in)
Elevation	+43° to 75°
Maximum firing range	14,200 m (46,600 ft)

The42 cmkurze Marinekanone L/12, orGamma-Gerät ("Gamma Device"), was a Germansiege gun built byKrupp. TheGamma-Gerät's barrel diameter was 42 cm (17 in), making it one of thelargest artillery pieces ever fielded. TheGamma-Gerät began development in 1906 and entered service with theImperial German Army in 1911. TheGamma-Gerät was the most powerful piece ofartillery fielded by the Imperial German Army, but due to its extreme weight was mostly immobile and could only be emplaced near permanent rail lines. As a result, theGamma-Gerät had limited effectiveness on theWestern andEastern Fronts of World War I.

A total of tenGamma-Gerät howitzers were produced, mostly during World War I, and were assigned to a total of sixartillery batteries, typically two guns to a battery. These batteries were deployed at various sieges and battles inBelgium,France,Poland, andSerbia. Alliedcounter-battery fire and internal detonations caused by faulty ammunition reduced the number of extantGamma-Gerät howitzers to a single gun by the end of World War I. ThisGamma-Gerät survived theaftermath of World War I and saw limited use inWorld War II by theWehrmacht to attack theMaginot Line andbesiege Sevastopol.

Beginning in the 1850s, advancements in artillery technology meant that modern artillery could fire from beyond the range of fortress guns. In response, military architects began placing forts in rings around cities or on a frontier to block approaching armies. Newhigh explosive artillery shells withtime-delay fuzes, which could penetrate earth to destroy masonry underground, made these forts themselves vulnerable to artillery. In response, the mid-19th century style ofpolygonal fort was abandoned in favour of forts built with concrete and mostly underground, with guns mounted in armoured, rotatingcasemates. Combining rings and fortified frontiers, France created a vast fortified zone on their border with Germany. Meanwhile, Belgium began construction of theNational Redoubt in 1888.^[1][2]

TheGerman Empire also fortified its borders, but Chief of theGeneral StaffHelmuth von Moltke the Elder desired to break through Franco-Belgian fortifications.^[3] Although German artillery had been effective during theFranco-Prussian War, by the 1880s the diameter of the German Army's most powerful gun, 21 cm (8.3 in),^[4] had become the standard thickness for fortress concrete.^[5] Moltke began requesting more powerful guns that same decade, which his successor,Alfred von Schlieffen, saw as key to hisplan to quickly defeat France by sweeping through Belgium. In 1893, theGerman Army'sArtillerieprüfungskommission [de] (Artillery Test Commission, APK) formed a secret partnership withKrupp to supervise development of a weapon that could break Franco-Belgian fortresses. Following a study that showed that a 30.5 cm (12.0 in) shell could penetrate modern fortresses, Krupp designed and built a 30.5 cm mortar, the Beta-Gerät. The Beta-Gerät was adopted into service in 1897 as theschwere Küstenmörser L/8, a cover name concealing its true purpose,^[a] making it Germany's first large artillery piece to have abreech and arecoil system. Further studies conducted by the APK in the mid-1890s showed that the Beta-Gerät could not penetrate the armor of modern Franco-Belgian forts, even with revised shells. Interest in an improved siege gun waned until theRusso-Japanese War, during which theJapanese Army used coastal mortars brought from Japan to end the 11-month longsiege of Port Arthur.^[7]

Helmuth von Moltke the Younger, Chief of the General Staff since 1 January 1906,^[8] sought a larger siege gun. In 1906, he instructed the APK to conduct further evaluation of the Beta-Gerät. The resulting study suggested a siege gun with a caliber as large as 45 cm (18 in), but the German Army opted for a 30.5 cm and a 42 cm gun. The former, the Beta-Gerät 09, had a greater range and accuracy than the Beta-Gerät, but was difficult to transport and could not penetrate fortress concrete. Only two were produced. Meanwhile, the 42 cm gun was designed in 1906 and its first model was delivered for testing in May 1909. After initial difficulties with penetration, the gun was accepted into the German Army in 1911 as thekurze Marinekanone L/12, or theGamma-Gerät. The first in-serviceGamma-Gerät was ordered in 1910, followed by another in 1911, three more in 1912, and an additional five during World War I. In total, ten were manufactured, along with 18 additional barrels. The power but near-immobility of theGamma-Gerät inspired further development by the APK, who addressed mobility in the development of theM-Gerät "Big Bertha" howitzer by pulling it with tractors.^[9]

TheGamma-Gerät was the largest and most powerful siege gun deployed by the Imperial German Army. Fully assembled, it stood 4.25 m (13.9 ft) high and 13.5 m (44 ft) long.^[10] It wasbreechloaded, making use of ahorizontally-sliding breechblock,^[11][12] and at full charge fired a shell at 452metres per second (1,480 ft/s) from a rifled,^[11] 6.7 m (22 ft) long barrel for a maximum range of 14,000–14,200 m (45,900–46,600 ft).^[11][13] The gun had atraverse of 46° and anelevation of 43° to 75°,^[11][12] adjusted with a hand-turned wheel on the front of the gun and another on the gun carriage for finetuning.^[10]

The gun weighed 150metric tonnes, ensuring that it could only be emplaced near permanent railways in a process that took 24 hours. For transport, theGamma-Gerät was disassembled and moved by rail in seven portions that weighed between 20 and 25 metric tonnes.^[b] Emplacement required the clearing of all nearby vegetation and the digging of a rectangular 2.25 m (7.4 ft) pit and the spinning of a spur off the nearest permanent railway to the site. A 25-metric-tonne rail-mountedgantry crane would then be used to assemble all seven portions of theGamma-Gerät. Its usual rate of fire was one shell every seven minutes and eight shells in an hour. The fastest recorded rates of fire were 19 shells an hour for a singleGamma-Gerät and 30 shells an hour for a two-gun battery.^[14]

German siege artillery had three types of projectiles:armour-piercing, high-explosive, and intermediate. The armour-piercing shell was designed to smash through concrete and metal armour, but was largely ineffective against reinforced concrete. High-explosive shells were fitted with two charges and could be set to have no delay, a short delay, or a long delay. If set to "no delay," then the shell burst on impact. If set to a delayed detonation, it could penetrate up to 12 m (39 ft) of earth. Finally, the intermediate, or "short shell," weighed half as much as the high-explosive shell and was fitted with a ballistic tip for range and accuracy. Shells for the 42 cm guns were generally 1.5 m (4.9 ft) long, weighed between 400 and 1,160 kg (880 and 2,560 lb), and were propelled via primer loaded into the gun with a brass casing. Siege artillery shells were produced in limited runs of varying quality. Beginning in early 1916, German siege guns began to suffer internal explosions due to faulty ammunition. As a result, crews were required to disembark from the gun before firing via alanyard.^[15]

Thekurze Marinekanone (KMK) batteries that formed withGamma-Gerät guns were 1 (2 August 1914), 2 (2 August 1914), and 4 (October 1914). In April 1916, Batteries 1 and 2 were split to form additional batteries: 8, 9, and 11. When Battery 8 had its guns destroyed by internal explosion in 1917, it was outfitted with two Beta-M-Gerät mortars, converted from the destroyedGamma-Gerät guns.^[16]

With the start ofWorld War I, all siege gun batteries were mobilised and assigned to theWestern Front. KMK Battery 2 was sent north toNamur, but could not arrive in time to participate in theSiege of Namur, while KMK Battery 1 was assigned to the6th Army inLorraine. As part of the 6th Army, it participated in the siege of theFort de Manonviller [fr] from 25–27 August 1914. During the 52-hour siege the battery had technical troubles and had to stop firing. KMK Battery 1 finally arrived at the then-ongoingsiege of Maubeuge in early September and joined the siege guns already present in obliterating FortsLeveau, Héronfontaine, Cerfontaine, andSarts. On 7 September 1914, Maubeuge's remaining garrisons surrendered.^[17]

The German defeat at theFirst Battle of the Marne prevented the siege guns at Maubeuge from being sent againstParis, so they were sent back into Belgium toAntwerp.^[18] The Belgian Army, which had retreated to the city on 20 August following the fall ofLiège, had made attacks on the German flank on 24–25 August and 9 September. In response, theIII Reserve Corps, from the1st Army, was sent to capture the city.^[19] The Corps arrived at Antwerp on 27 September, partially surrounding it and massing at its southern side. The next day, KMK Battery 2 opened bombardment against the Fort de Wavre-Sainte-Catherine, which was destroyed on 29 September by a magazine detonation caused by a 42 cm shell. KMK Battery 2 then shifted its fire to theFort de Koningshooikt [nl], which surrendered on 2 October.^[20] Beginning on 7 October and lasting the next two days, Antwerp's defenders began withdrawing from the city, which then surrendered on 10 October.^[19] With the fall of Antwerp, KMK Battery 2 was attached to the4th Army to aid in its capture of the Channel ports, and occasionally shelledNieuport,Ypres, andDiksmuide.^[21]

On 27 February 1915, KMK Battery 1 arrived on theEastern Front with the8th Army and joined the ongoing attack onOsowiec Fortress. Although the fortress was made of masonry, it survived because the artillery had no spotters to guide its fire and because of effective counter-battery fire from the fortress. After five days, the siege guns were withdrawn and the fort was besieged until August. On 8 August, KMK Batteries 1 and 4 fired onKaunas Fortress to support theXXXX Reserve Corps. While slow, the bombardment was highly effective because of outdated masonry construction, and the Germans took four forts altogether on 16–17 August. The Russians evacuated from the city and fortress the next day. The last deployment ofGamma-Gerät guns in the East was theGerman invasion of Serbia. On 6 October 1915, KMK Batteries 1 and 4 opened fire on Serbian fortifications east ofBelgrade to support the crossing of the11th Army, made the next day. Battery 1 briefly fired onSmederevo Fortress, but the fortress was undamaged when it surrendered on 11 October.^[22]

KMK Batteries 1 and 4 were transferred back to the Western Front in early 1916 and were assigned to the5th Army for the upcomingBattle of Verdun.^[23] The battle began on 21 February with an intense, nine-hour artillery barrage.^[24] The 42 cm guns were tasked with bombarding FortsDouaumont,Vaux,Souville [fr], andMoulainville [fr], the most modern fortresses atVerdun, to silence their guns and prevent French units from rallying at them. However, despite heavy shelling by all thirteen 42 cm guns, the forts were only lightly damaged. At the same time, French counter-battery artillery and internal explosions plagued German siege guns; KMK Batteries 2 and 8 lost aGamma-Gerät each while KMK Battery 9 lost its onlyGamma-Gerät. In July, siege batteries began to be withdrawn north to theBattle of the Somme, and east to Romania. KMK Battery 4 remained at Verdun, while Battery 1 attackedArras andLoos-en-Gohelle in June and July.^[25]

In the last two years of the war, siege guns saw limited use and negligible effect on the Western and Eastern fronts. In 1917, KMK Battery 8 were denuded of theirGamma-Gerät guns by internal explosion and Allied counter-battery fire and was reequipped with an ineffective war-time iteration of the M-Gerät. Ahead of thefinal German offensive of the war, KMK Battery 4 was assigned to the17th Army on theSomme. It was moved to join the 1st Army atReims in July 1918. By the end of the year, the battery was one of five remaining siege gun batteries in the German Army and wielded a singleGamma-Gerät.^[26]

Three German siege guns survived to the end of World War I. Two were surrendered to the United States and the third,^[27] the finalGamma-Gerät, was disassembled and hidden from Allied inspectors in Krupp'sMeppen facilities.^[27][28] In 1937, at the request of thenew German Army,^[29] the gun was reassembled for use in the development of concrete-penetrating shells.^[11][30] WhenWorld War II began, this survivingGamma-Gerät was put back into military service. In 1940, it was used to bombard the fortresses of Liège and theFortified Sector of the Sarre, a portion of theMaginot Line. TheGamma-Gerät was placed in storage after thefall of France until early 1942, when it was sent to bomb the fortresses ofSevastopol, which it shelled from February until exhausting its munitions on 13 June.^[31] It was also deployed atKronstadt in 1942, but did not fire a single shot there.^[27] In 1944, theGamma-Gerät was removed from active service and returned to Germany.^[32] Its post-war fate is unknown.^[27] Production of 42 cm shells was resumed to supply theGamma-Gerät and continued to as late as July 1944.^[11]

• Big Bertha (howitzer)
• List of the largest cannon by caliber

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• Hogg, Ian V. (1997).German Artillery of World War Two. Greenhill Books.ISBN 978-1-85367-480-8.
• Kinard, Jeff (2007).Artillery: An Illustrated History of Its Impact.ABC-Clio.ISBN 9781851095612.
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• Romanych, Marc & Rupp, Martin (2020).World War II German Super-Heavy Siege Guns. Illustrated by Adam Tooby and Andrea Ricciardi di Gaudesi. Osprey Publishing.ISBN 978-1-47283-717-2.
• Tucker, Spencer, ed. (2014).World War I: The Definitive Encyclopedia and Document Collection. ABC-Clio.ISBN 978-1-85109-964-1.

• Engelmann, Joachim & Scheibert, Horst.Deutsche Artillerie 1934–1945: Eine Dokumentation in Text, Skizzen und Bildern: Ausrüstung, Gliederung, Ausbildung, Führung, Einsatz (in German). C. A. Starke.OCLC 5673937.
• Gander, Terry & Chamberlain, Peter (1979).Weapons of the Third Reich: An Encyclopedic Survey of All Small Arms, Artillery, and Special Weapons of the German Land Forces, 1939–1945. Doubleday.ISBN 0-385-15090-3.
• Jäger, Herbert (14 September 2001).German Artillery of World War One. Crowood Press.ISBN 1-86126-403-8.
• Schirmer, Hermann.Das Gerät der Artillerie vor, in und nach dem Weltkrieg: Das Gerät der schweren Artillerie. Bernard & Graefe.OCLC 29133423.
• Taube, Gerhard (1981).Die schwersten Steilfeuer-Geschütze, 1914-1945: Geheimwaffen "Dicke Berta" und "Karl" (in German). Motorbuch Verlag.ISBN 978-3-87943-811-2.

• Media related toKurze Marine-Kanone 12 L/16 (Gamma-Gerät) at Wikimedia Commons

• World War I howitzers
• World War I artillery of Germany
• World War II artillery of Germany
• 420 mm artillery
• Siege artillery

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