I am looking for information and pictures of the German 8.8 cm L/30 quick-firing C/89: I am especially interested in the land batteries.
The breech is of a so-called spherical wedge type (Rundkeilverschluss in German). The wedge that closes the breech is actuated using the two-spoke lever to the right of the gun and some sort of short acme screw. When open, the breech block would move to the right bringing the round opening behind the barrel through which the cartridge can be loaded. Missing is the seat for the training number.
This type of gun on this mounting was used as light/medium armament against torpedo boats on destroyers, cruisers, battle ships, land batteries etc. It was also the main armament of larger torpedo boats.
More details can be found in this book produced by the Naval Office of the Imperial German Navy:
REICHS-MARINE-AMT (1898): Die Schnelllade-Kanonen der Schiffs-Artillerie (für Einheitspatronen) und ihre Munition.- 273 p., Berlin (E.S. Mittler und Sohn). (the two enclosed pictures are from the book) - " - (1895): Exercirreglement für die Marine-Artillerie, Nr. XXXIV. Für die 8,8 cm Schnellade-Kanone L/30 in Mittel-Pivot-Lafette C/89.- Berlin (E.S. Mittler und Sohn). (these are the instructions for training with the gun)