The Krupp K5 series all were consistent in mounting a 21.5 m long gun barrel in a box mounting. This mounting was then mounted on a pair of 12-wheel bogies designed to be operated on commercial and military rails built to German standards. This mounting did not permit full gun traverse, but instead the carriage had to be aligned on the rails first, with only minimal fine levelling capable once halted.
The main barrel of the K5 is 283 mm in calibre, and is rifled with twelve 7 mm grooves. These were originally 10 mm deep, but were shallowed to rectify cracking problems.
The K5 was the result of a crash program launched in the 1930s to develop a force of railway guns to support the Wehrmacht by 1939. K5 development began in 1934 with first testing following in 1936. Initial tests were done with a 150 mm barrel under the designation K5M.
Production led to eight guns being in service for the Invasion of France, although problems were encountered with barrel splitting and rectified with changes to the rifling. The guns were then reliable until the end of the war, under the designation K5 Tiefzug 7 mm. Three of them were installed on the English Channel coast to target British shipping in the Channel, and proved successful at this task.
Towards the end of the war, development was done to allow the K5 to fire rocket-assisted projectiles to increase range. Successful implementation was done for firing these from the K5Vz.
A final experiment was to bore out two of the weapons to 310 mm smoothbore to allow firing of the Peenemünder Pfeilgeschosse arrow shells. The two modified weapons were designated K5 Glatt.
Several other proposals were made to modify or create new models of the K5 which never saw production. In particular, there were a number of plans for a model which could leave the railway by use of specially modified Tiger II tank chassis which would support the mounting box in much the same manner as the railway weapon's two bogies. This project was finally ended by the capitulation of Germany.
