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.
If you can provide any more information about these guns, please write
to the site administrator.