The 28 cm Haubitze L/12 was a design of the First World War. Recoil forces were absorbed by a combination of the gun cradle moving up an inclined plane and two hydro-pneumatic or hydro-spring recuperator cylinders, one on each side of the carriage. It was mounted on a turntable which was fixed to a wooden firing platform. For transport it broke down into four loads, the barrel, cradle, turntable and firing platform, each carried by a three-axle trailer. It required three to four days to emplace for firing. An ammunition crane was fixed to the carriage for ease of loading.
It fired a 350 kg (770 lb) high-explosive shell to a range of 10,400 metres (11,400 yd).
Engelmann, Joachim and Scheibert, Horst. Deutsche Artillerie 1934-1945: Eine Dokumentation in Text, Skizzen und Bildern: Ausrüstung, Gliederung, Ausbildung, Führung, Einsatz. Limburg/Lahn, Germany: C. A. Starke, 1974
Gander, Terry and Chamberlain, Peter. Weapons of the Third Reich: An Encyclopedic Survey of All Small Arms, Artillery and Special Weapons of the German Land Forces 1939-1945. New York: Doubleday, 1979 ISBN 0-385-15090-3
Hogg, Ian V. German Artillery of World War Two. 2nd corrected edition. Mechanicsville, PA: Stackpole Books, 1997 ISBN 1-85367-480-X