Originally Posted by Angry_bald_guy
Where can I get the upper and how much would I be likely to spend?
I watched Gunbroker for a few weeks when I saw one with 2 mags and sights for around $650 and at the time they were being offered for $699 and no mags or anything
I'm seeing the best prices on Gunbroker for $629 and included 2 mags and a modified Pmag to use as a brass catcher. PW ARMS AR-57, AR Five-seven, AR57, NEW, w/ 2 Mags : for AR-15 at GunBroker.com
Mags are typically around 35-50 bucks depending on if they are factory or aftermarket. If you keep your eyes open you might be able to do better than that or you can probably order one from about any dealer that carries AR parts.