Sheet Metal Guns
It's time again to point out how futile the concept of gun control really is. I've discussed 3D printed firearms because they're a neat demonstration of how manufacturing technology is advancing. But guns have been around for hundreds of years so it's safe to say that manufacturing them isn't too difficult. The Firearm Blog has a post about a semi-automatic pistol made from sheet metal. It's an ugly looking thing but it supposedly works and the blueprints are available [PDF] for download.
What's nice about this design is the simplicity of manufacture. Sheet metal can for the most part be shaped with hand tools. Although I doubt that this gun is terribly accurate it doesn't have to be if used correctly (as in used at short ranges).