Digging around in the parts bin this morning, I came up with an old USGI M16 upper receiver assembly. Fortunately, I had a 1992 E. A. Company(now defunct) J-15 pre-ban stripped lower receiver currently laying dormant. Naturally I had both a take down pin and a hinge pin on hand to mate them together. Yes, I know the curved fence around the hole for the magazine release button is shaped incorrectly. But hey, the market was not exactly flooded with stripped mil-spec receivers at the time before the ban.
Now the question remains, what should I build? My mind is leaning towards a retro look. Should I go with the Vietnam era M16 with pencil barrel and duck bull flash hider? Or perhaps the later M16A1 like I used in Basic Training?
Then of course I could go with the rare Vietnam vintage XM177E2.