Mega Machine Shop does parts for the aerospace industry, doing AR15 receivers on the side. I found quality to be top notch. I just finished a build using Mega's upper and lower receivers and all went perfectly. I'm thinking of getting a couple of more for future builds. Here's a few good places that I know of that sells Mega receivers ..............
http://www.rainierarms.com/
E-mail for Dane's Armory: sales@danearmory.com
http://www.ar15web.com/categories.php
http://www.carricozarmory.com/
And here's the result ...............
http://coloradoshooting.org/v-web/bu...pic.php?t=3594