20 . 3 cm K ( E ) The 20 . 3 cm Kanone ( E - Eisenbahnlafette ( railroad mount ) ) was a German railroad gun used on coast - defense duties in Occupied France and Belgium during World War II . Eight guns were transferred from the Navy ' s stocks after having become redundant with the loss and sale of several Admiral Hipper - class heavy cruiser s and were delivered in 1941 and 1942 . Design . As part of the re - armament program initiated by the Nazis after taking power in 1933 the Army High Command " ( Oberkommando des Heeres – OKH ) " ordered Krupp to begin work on new railroad artillery designs , but they would take a long time to develop . Krupp pointed out that it could deliver a number of railroad guns much more quickly using obsolete guns already on hand and modernizing their original World War I mountings for which it still had drawings available . OKH agreed and authorized Krupp in 1936 to begin design of a series of guns between for delivery by 1939 as the Emergency Program ( " Sofort - Programe " ) . Eight " 20 . 3 cm SK C / 34 " guns intended for the Admiral Hipper - class heavy cruiser s were made available for the Army . Krupp was able to adapt the design of the World War I - era 21 cm SK " Peter Adalbert " for the smaller guns . Two differences were the substitution of an ammunition crane for the overhead ammunition trolley system of the " Peter Adalbert " and the removal of the latter ' s under - carriage pivot mount and rollers . Sources differ on how much the gun could traverse on its mount . Kosar and François quote 2 . 4° , while Gander and Chamberlain say 14 ' , but Hogg says not at all . Whatever the exact figure , the gun could traverse only enough on the mount itself for fine corrections , coarser adjustments had to be made by turning the entire mount on the Vögele turntable . The turntable ( " Drehscheibe " ) consisted of a circular track with a pivot mount in the center for a platform on which the railroad gun itself was secured . A ramp was used to raise the railway gun to the level of the platform . The platform had rollers at each end which rested on the circular rail for 360° traverse . It had a capacity of , enough for most of the railroad guns in the German inventory . The gun could only be loaded at 0° elevation and so had to be re - aimed for each shot . Four guns each were delivered in 1941 and 1942 . Photographic evidence exists of a " 20 . 3 cm K ( E ) " carried by two six - axle Culemeyer - Strassenfahrzeug lowboy trailers and moving by road . Ammunition . The Army failed to appreciate that the naval ammunition was not in its inventory until after the guns had already been produced . It asked Krupp to modify the guns to use its standard ammunition , but it proved uneconomic to do so . It deployed the guns in fixed locations , i . e . on coast - defense duties , to minimize the burden on its logistical system . Ultimately the Army ordered eight 21 cm replacement barrels , but only four had been built before six weapons were captured or destroyed during the Battle of Normandy and the whole exercise became futile . It used the German naval system of ammunition where the base charge was held in a metallic cartridge case and supplemented by another charge in a silk bag which was rammed first . Combat history . By 8 July 1942 two guns were assigned to " Battery 687 " and spent the rest of the war on coast defense duties at Lissewege , Belgium . This battery was later redesignated as " 4th Battery , Army Coast Artillery Regiment ( 4 . / Heeres - Küstenartillery - Regiment ) 1240 " . Four weapons were assigned to " Battery 532 " in Paimpol , Brittany . This battery was later redesignated as " Army Coast Artillery Battery 1272 " . " Battery 685 " was stationed in Auderville - Laye with 2 guns to defend the tip of the Cotentin Peninsula until being destroyed after the Americans isolated the peninsula on 18 June 1944 . It was later redesignated as " 3rd Battery , Army Coast Artillery Regiment 1262 " .