One of the last things I worked on while at Parker Signs for the Gold Star Military Museum in Des Moines, IA. Made entirely out of HDU. We laminated several blocks together and then had them roughly lathed. The last foot or so of the cannon was routed on the CNC to carve the end engraving as well as rough out the rifling of the inner barrel. We did a pretty nifty trick while painting it to achieve a cast metal texture.