The 21 cm heavy field gun (K. 39), an original Skoda design, was taken over by the German Army shortly after the invasion of Czechoslovakia. For transport, the equipment may be broken down into three loads, each of which is mounted on two 2-wheeled, pneumatic-tired bogies.
The piece consists of an autofrettaged monobloc barrel and loose liner, and a breech ring. The breechblock is of the interrupted screw threaded type, incorporating an obturator pad, obturator spindle and percussion firing lock. On recoil, the piece slides in a cylindrical sleeve in the cradle.
The upper carriage is fitted to a turntable which revolves on a ball race mounted in the platform. The platform consists of a rectangular sheet steel box which is dug into the ground. Four removable arms located at the corners of the platform support it by bearing on the ground by means of special feet. During transport, the arms are lowered and serve to support the platform on its bogies.
The traversing and elevating mechanisms, each with two-speed gearing, are operated from handwheels on the left of the carriage.
Four types of ammunition are used in the gun: the original Czech high explosive shell; a German version of the same shell with the base fuze omitted; an anti-concrete shell with ballistic cap and base fuze; and an armor-piercing shell with base fuze. It is loaded at 8° elevation with the help of a special 2-wheeled shell trolley.
There are two other versions of the weapon, the K. 39/40 and the 39/41. Although the two later models are modifications of the original Skoda design, they do not differ in main performance details
SPECIFICATIONS
| Caliber | 210 mm (8.27 ins.) | |
| Weight (traveling position) | Three loads approx. 16 1/2 tons each | |
| Weight (firing position) | 37.2 tons | |
| Length of barrel including breech ring | 31.3 ft. | |
| Muzzle velocity (max.) | 2,625 f/s | |
| Max. range (horizontal) | 32,800 yds. | |
| Traverse | 360° | |
| Wt. of max. charge | 82.8 lbs. | |
| Elevation | 45° | |
| Depression | -4° | |
| Ammunition | H.E.; Anti-concrete; A.P. | |
| Wt. of projectile | All 298 lbs. |
German: p. 100.3 (May 1, 1945)