Bofors 40 mm AA Gun

And now to create a suitable base ... 

the base is half of a Ferrero Rocher box, sprayed black and filled with a couple of pours of Plaster of Paris. Sandbags are Sculpy, and the plants are bristles from a whitewash brush, with some of the tips scorched over a candle to look like seed heads. Just a few rifles and canteens left to place once they are painted.