This is a gun enclosure meant for rapid prototyping. It is for the 6mm scale (300:1) version of Games Workshop's Warhammer 40K (known as Epic). This part will plug into a chassis already sold by GW's subsidiary, Forge World.

The rendering was done in Hypershot. HS doesn't seem to be very good at handling 3DM, so I had to export to OBJ, causing a few weird artifacts, like the closed-in barrel.