The 420mm Gamma Mörser mortar was designed and built by Krupp before WWI as a super heavy siege howitzer. During WWI, siege howitzers were used in the capture of the Kovno fortress. After the end of WWI, all but one of the siege howitzers were dismantled. During the Second World War, a 420mm mortar was used during the siege of Sevastopol in 1942.
History of creation
Long before the First World War, the Krupp factories began to develop a whole series of super-heavy weapons for the siege of heavily fortified fortresses. The development of the Gamma Mörser mortar was the third project in this series and was essentially an enlarged 30.5 cm Beta-Gerät. Krupp's engineers already had good experience in building super-heavy guns - four "40 cm L / 35 guns" were delivered to Italy for installation in the coastal twin towers in Taranto and La Spezia.
The beginning of development - the decision of the Prussian General Staff, it was decided to equip the army with large guns for the siege of enemy fortresses. In April 1909, the prototype mortar was ready for testing at the Krupp test site. Tests showed the promise of the gun and in 1911 the mortar was delivered for artillery military trials. The tests were successful.
The General Staff developed a plan for an attack on France (the French fortresses of Namur and Liege), with a simultaneous attack on Belgium. This would require eight 420mm Gamma Mörser mortars and 16 30.5 cm Beta-Gerät mortars. In 1913-1914, four more 420mm mortars were built. Before WWII, 5 Gamma Mörser mortars were built, 5 more were built during the war. They planned to build about 18 more copies. The only surviving mortar that took part in the Second World War was hidden by the Germans at the Krupp training ground in Meppen. It was used in the 1930s to test the properties of concrete.
Device and design
The mortar belonged to the class "Bettungsgeschütz" - installation on a concrete foundation. To install the mortar, a lifting rail crane was required. The mortar was serviced by 250 people, transportation to the place of use took place by rail - on ten platforms. The mortar was assembled and installed within 4 days, it was required to wait for the concrete foundation to solidify. Horizontal aiming angles 23 degrees, vertical pointing angles up to 75 degrees. The breech of the "Welin" system is of the screw type. The recoil mechanism consisted of two hydraulic brakes (upper part of the barrel) and a hydropneumatic knurler (lower part of the barrel).
Ammunition
During WWI, the 420mm mortar used two types of ammunition (concrete-piercing and high-explosive) weighing 886 kilograms (initial speed 370 m / s) and 760 kilograms. During the Second World War, a concrete-piercing shell weighing 1003 kilograms was used. Charging of a separate type, powder charges with a total mass of up to 77.8 kilograms were used. The number of powder charges - from 1 to 4 units.
Before the Second World War, an artillery reserve of the main command of the ground forces was created in Germany. The only 420mm mortar "Gamma Mörser" goes to his disposal, in the division of super-heavy guns. In 1942, as part of the 459th separate battery, the mortar took part in the artillery battle for Sevastopol. It was used in battles on the Maginot Line, suppressing the uprising in Warsaw.
Main characteristics of 42 cm kurze Marinekanone L / 16:
- caliber - 420mm;
- combat weight - 140 tons;
- barrel length - 6.72 meters;
- guidance angles horizon / vertical - 23 / 43-75 degrees;
- projectile speed (1003 kg) - 452 m / s;
- rate of fire - one shot every 8 minutes;
- range of destruction up to 14.2 kilometers;
- angle of rotation - 46 degrees.
