Well after making a file to print standard 30 round magazines they have now succeeded in creating a file to print a working AR-15 lower downloadable on the internet and printable on the more inexpensive 3D printers.
http://www.youtube.com/watch?feature=player_embedded&v=tAW72Y_XPF4
http://www.youtube.com/watch?feature=player_embedded&v=tAW72Y_XPF4