Yes, but if you use these instructions, which they've limited the distribution of, you'd be hard pressed to explain where you got them from.

ATF agent: Oh, you got that from a torrent? Did you also seed the file?

You can see where this is going, and it doesn't have a happy ending.

If you do make one of these though, for the love of God embed a chunk of metal. These things wouldn't be legal without it (metal detectors).