24-cm Kanone 3
During 1935 Rheinmetall began design work on a new heavy gun to meet a German army requirement for a longrange counterbattery gun firing a heavy projectile. The first example was produced during 1938, and a small batch was ordered soon after as the 24-cm Kanone 3 (24-cm K 3). The K 3 was a fairly massive piece of artillery that used the 'double recoil' carriage coupled to a firing table that could be easily traversed through 360°. The barrel could be elevated to 56° and thus fired in the upper register to ensure that plunging fire against fortifications and field works would make the shells as effective as possible.
The K 3 carriage was well endowed with all manner of technical novelties. In order to make the gun as mobile as possible the whole gun and carriage were broken down into six loads, and assembly on site was made as easy and rapid as possible by a number of built-in devices such as ramps and winches. Various safety measures were incorporated in case assembly was in some way incorrect; for instance, incorrect breech assembly left the gun unable to fire. Other safety measures ensured that if a winch cable broke the component involved could not move far enough to cause any damage. For all these measures it took some 25 men 90 minutes to get the gun into action. Once the gun was in action a generator, an integral part of the carnage, was kept running to provide power for the gun's services.
Not many K 3s were produced; most references mention eight or 10. They were all used operationally by one unit, schwere Artillerie Abteilung (mot) 83. This motorized artillery battalion had three batteries (each with two guns), and it was in action all over Europe from the USSR to Normandy.
The K 3 was the subject of much experimentation by German designers. Special barrels were produced in order to fire experimental projectiles with body splines that aligned with the barrel rifling as the projectile was rammed into the chamber. Other barrels fired projectiles fitted with sabots to increase range, and there was even a device fitted over the muzzle that 'squeezed' back skirts around special sub-calibre projectiles, again in an attempt to increase range. Some smooth-bore barrels were produced to fire the long-range Peenemünder Pfeilgeschosse (arrow shells).
By a quirk of production schedules the Rhemmetall-designed K 3 weapons were actually manufactured by Krupp of Essen. The Krupp engineers were not highly impressed by the engineering of the K 3 and decided they could do better, so producing their own version, the 24-cm K 4. This was a very advanced design with the mounting carried on the move between two turretless Tiger tanks. There was even supposed to be a selfpropelled version, but in 1943 the prototype was destroyed during an air raid on Essen and the whole project was terminated.
The K 3 was still in action when the war ended and at least one example fell into US Army hands. This was taken to the United States and underwent a great deal of investigation. Once the trials were over it went to Aberdeen Proving Grounds in Maryland, where it can still be seen.
Specification 24-cm K 3
Calibre: 238 mm (9,37 in)
Length of piece: 13.104 m (42 ft 11.9 in)
Weight: travelling (six loads) 84636 kg (186,590 lb) and inaction 54000 kg (119,050 lb)
Elevation: -1° to +56° Traverse: on turntable 360° and on carriage 6°
Muzzle velocity: 870 m (2,854 ft) per second
Maximum range: 37500 m (41,010 yards)
Shell weight: 152.3 kg (335,78 lb)