Knut Erik Hagen took these photos in March, 2004 at the Forsvarsmuseet (Armed Forces Museum), at Akershus Castle, in Oslo.
The gun is probably the German System Erhardt Schnellfeuerkanone C/1901. The three sets of photos probably depict the same model, but this is not certain. I do not know if it saw service in WWI It also appears to be similar to 75mm Modell 1902 of Swedish make.
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