Thanks thats a good idea about the college class. I saw a tv program where they made a silicone mold like you said. Thats the route I'll go because If I'm going trough all the trouble I might as well make a bunch. As far as the strength I doubt I'll get one as strong as a factory one. But one of the great things about the ar is that the lower really just holds the parts in alignment and doesn't get much stress. I'm sure for limited use you could even make one out of a can of the automotive fiberglass bondo.