Krupp K5

28-cm-Kanone 5 (E)
K5 railway gun in France 1945 c.
Type	Railway Gun
Place of origin	Nazi Germany
Service history
Used by	Wehrmacht
Wars	World War II
Production history
Manufacturer	Krupp
No. built	25
Specifications
Weight	218 t (215 long tons; 240 short tons)
Length	Travel: 30 m (98 ft) Combat: 32 m (105 ft)
Barrel length	21.539 m (70 ft 8 in) L/76.1
Shell	255 kg (562 lb)
Caliber	283 mm (11.1 in)
Elevation	+50°
Traverse	2°
Rate of fire	15 rounds per hour
Muzzle velocity	1,120 m/s (3,675 ft/s)
Maximum firing range	64 km (40 mi)

The Krupp 28-cm-Kanone 5 (E), in short K5 with the (E) signifying Eisenbahnlafette (railway car gun-mount), was a heavy railway gun used by Germany throughout World War II.

Krupp's K5 series were consistent in mounting a 21.5 metres (71 ft) long gun barrel in a fixed mounting with only vertical elevation of the weapon. 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. This mounting permitted only two degrees of horizontal traverse. The carriage had to be aligned on the rails first, with only minimal fine leveling capable once halted. Hence the gun could only fire at targets tangential to an existing railway track.

To track targets needing greater traverse either a curved length of railway was used with the gun shunted backwards or forwards to aim; a cross-track was laid with the front bogie turned perpendicular to the rest of the gun and moved up and down the cross-track to train the weapon; or for 360 degree traverse, the so-called "Vögele Turntable" could be constructed, consisting of a raised rail section (the "firing bed") carrying the gun, running on a circular track with a central jack to raise the gun during traverse and to take some of the enormous weight.

The main barrel of the K5 is 283 mm (11.1 in) in calibre (caliber), and is rifled with twelve 7 mm (0.28 in) grooves. These were originally 10 mm (0.39 in) 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 at the Firing Test Range Rügenwalde-Bad (German: Schießplatz Rügenwalde-Bad) in Farther Pomerania at the South coast of the Baltic Sea. 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, but proved unsuccessful at this task.