On June 3, 1942, the commander of the 11th German Army, General Mannstein, started to rain shells upon Sevastopol, the Soviet fortress in the Crimea which was considered to be the most fortified stronghold of World War 11. 1300 guns of various types were employed during the siege. Among them, the 80cm railway gun Dora, the 42cm Morser Gamma and the 60cm Morser Karl fired their big shells into seemingly invincible Sevastopol. Finally, as a result of continuous shelling lasting one month heroic Sevastopol fell on July, 3.

During World War II the Germans employed as heavy field guns various types of gun such as the 15 cm Cannon. the 21cm Morser, the 21cm Cannon, the 24cm Howitzer, the 24cm Cannon, the 35.5cm Howitzer. the 42cm Morser Gamma and the 60cm Morser Karl the latter of which was the largest of all the self-propelled guns.

In 1937, the germans projected a production of a heavy artillery gun to be employed against fortresses. Designed with an idea of a super-heavy self-propelled Morser capable of discharging highly efficient shells of high trajectory which were powerful enough to penetrate thick concrete, the first trial equipment was built by the Rhine Metal Co. in 1939. This was the 60 em Morser Karl. At first it was developed for use in the campaign against France, but since France had surrendered, it was put to use for the first time on the Russian front and saw action in the siege of Sevastopol. It was also employed in the Brest-Litovsk and Warsaw uprisings.

Altogether six of the 60 em Morser Karl (Gerat 040) were built. The suspension system was of two kinds of torsion bar spring method, that is, one with eleven road wheels and eight return rollers on each side and the other with eight load wheels and eight return rollers. The engine was a Daimler-Benz MB 507 12 cylinder liquid-cooled diesel engine providing a maximum speed of 10 km/h. To soften recoil on firing, the body was lowered by adjustment of load wheels. Special attention was paid to the conveyance of the Karl which was beyond the genera11y, accepted idea of a self-propelled gun. When it was transported by rail, two trucks with five sets of special wheels were provided on which the Karl was mounted. In case of transportation by road, the Karl was taken apart. For its assembly, a 35t. crane and two 7t. cranes were required.

The Kari had a range of 6,800 m at best. Therefore. to extend the range, a barrel of 54cm calibre and 7. 1 m in length was manufactured. Some Karls were equipped with it instead of the 60cm calibre gun to become the 54cm Morser, designated Gerat 041 With the longer range of 10,400m