I was using both Fritz Hahn and primary sources - one OKH report dated 02.10.1939 about ammo expenditure by armies (3., 4., 8., 10. and 14. in Poland, as well as 1., 5. and 7. in the West) until 01.10.1939, and another report by OKH written on 27.09.1939 about expenditure by armies (same armies as above) until 24.09.1939. And this OKH report from 27.09.1939 says that 10. Army fired 12 rounds of 24cm K3 ammo (other armies - 0), while Fritz Hahn claims that in total 183 rounds were fired in Poland (I forgot until which date is Hahn's data), and the report from 02.10.1939 says that 264 rounds were fired. Check also my old post here:(please use primary sources only, not Hahn)
http://forum.axishistory.com/viewtopic. ... 4#p1584442
I'm writing this post from memory because the last time I analyzed those sources was back in 2011.
So maybe I confused something. But anyway - I saw three different numbers in two reports and Hahn.
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Edit:
No, sorry - in that report until 24 IX ammo expenditure of 24cm K3 type was not reported.
Only between 24 IX and 1 X those guns were firing rounds. Probably during the siege of Warsaw and Modlin?
But - surprisingly - the loss of 2 guns took place before 24 IX, and thus before they were firing rounds.
Anyway - there is also that source which says the total expenditure was 264 rounds (Hahn says 183).
I must find my notes regarding those sources, I have them somewhere... But where.