It was basically a sand and paint job. Firstly i took my dremel to it to sand off the rough 'seam' lines. I also deepened the barrel holes. Once this was done i then filled in an gaps (formed by bubbles normally) with epoxy resin, and resanded those areas.
I then gave the whole model about 20 thin coats of black spray paint, I added further detail using silver leaf paint to the switches, and brown to the handle.