I'm looking for wartime pictures of 15cm K18 heavy gun. I know very few photos of this gun even though 101 copies were manufactured according to various sources.
Secondly I have a small doubt. I have on my hard drive two photos (from Ebay) showing this gun with different wheels than normal.
Standard wheels had spokes while these two photos show wheels with 8 round holes. The question is: Were these wheels used only in the first production copies or were used two different types of wheels along the time of manufacturing of this gun?
Also, in my third photo these rare wheels with 8 holes can be seen in the barrel trailer (the carriage can not be seen very well), while in my second photo these wheels only are used in the carriage and not in the barrel trailer (with standard wheels).

My first photo shows the gun and trailers with standard wheels, to compare.
Thanks in advance. Regards Sturm78