Found this over at Calguns:

"As of Apr 22, the ATF wrote a letter stating that they consider 80% lower build parties to be illegal. For this reason, we no longer offer them. We disagree with their opinion, but there is little we can do to challenge it at this point. We do sell jigs that make finishing your lower a pretty simple process. With a jig, drill press, and 3 hours of your time, you can easily finish your lower at home."

http://www.calguns.net/calgunforum/s...d.php?t=750262