spymongoose has a couple of them, but the bodies are pretty mangled. There's only enough parts to build one complete gun, but he has 2 full sets of internals. I also suggest (if you haven't already done so), going to vintagerex.com. They have the exploded view of these guns there. Once you have a set of guts and the diagram, they're not too hard to figure out. As far as building your own from scratch, I don't envy you. The best thing to do is to find one complete, working or not. It takes some patience, but it's worth it.