Sergey Kamotsky has released his 1:50 model of the 9inch Mortar M1892 into the public domain - this had been a commercial model.
I've fixed up the px/inch problem which seems to happen with Russian graphic software read by western software and wrapped the model into a .pdf. The model does print correctly on A4 - I verified this.
The M1892 mortar is a pretty standard design mortar used in coastal defence and fortresses at the end of the 19th century. The M1892 was used in the Russo-Japanese war of 1904-5 and in WW1.
Usual location:
Landships II
Regards,
Charlie