This gondola was then mounted on a pair of 12-wheel bogies designed to be operated on commercial and military rails built to German standards.

K5 development began in 1934 with first testing following in 1936 at Darlowo (German: Schießplatz Rügenwalde-Bad) in the former Farther Pomerania at the South coast of the Baltic Sea.

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.

Two K5 guns, named Robert and Leopold by German crews, were shipped to Italy to help counter the Allied landing at the town of Anzio in February 1944.

On 18 May 1944 the guns fired off their remaining ammunition and then escaped along the coastal railroad into the rail yard in Civitavecchia, in preparation for evacuation.

A final experiment was to bore out two of the weapons to 310 mm (12.2 in) smoothbore to allow firing of the Peenemünder Pfeilgeschosse arrow shells.

[4] The guns were discovered on a railroad siding in the town of Civitavecchia, on 7 June 1944, shortly after the allies had liberated Rome.

In early 2011 it was moved to Fort Gregg-Adams, Virginia as a result of the 2005 Base Relocation and Closure (BRAC) Act.