This photo is new to me but the tank isn't - I have another photo of it. Sadly though I haven't identified it. There is a serial number there (starts with 2, maybe 20?) but I just can't read it.
I don't think the gun is at full recoil by the way. Partial recoil perhaps? I could be wrong.
As a trivial observation, you will note the caption ends with "1918". Oddly, it is not in typical German numeric, rather it appears to have been added later in "American" style. One of those oddities boring people take note of.
