Summary

B-25G with 75mm gun

model in full dimensions in blender 2.79b and scaled to 1/100 for the .stl file
scale down to 35% in the slicer.

catching up with test prints.
The picture was printed with a stupidly thick layer height for such a scale model; .2mm ( I normally use .08 or .12mm

and the 75mm gun is still noticeable!