A small project,just to see if I could do it.Page 17 of Sky Galleons shows a picture of a Martian Lob Gun.
I have never seen a Lob Gun like the sketch before.Most people use a mortar in games as the weapon in the canon works like a mortar.But while looking at the picture it came to me that parts of GW WH Empire kits could be used to make something like the sketch.
So one Empire canon,on weapon mounting from the Empire tank and the tanks smoke stack top.Cut the canon in about half along the moulding.Glue the 'Chimney stopper'in place after a little carving of the plastic,a bit og green stuff and add the rest of the barrel to it.
An option you may like to take is to cut a loading hatch where the Empire Coat of Arms are,or not?
Its still to have a front plate and a base but it seems to of worked.
Edited.Finished and painted.