I've got a complete upper for sale, here are the specs on it:
-Dolos quick change barrel system
-Green Mountain 5.56 chamber 7.5" chrome lined pistol barrel standard A2 flash hider
-Yankee Hill clamp on low pro gas block
-M16 bolt from AIM surplus w/ Diamondback charging handle
This upper has about 60 rounds down the pipe, neat little package, but I'm selling off some toys to get a down payment together for a house. The dust cover on this is engraved "Boom Boom", it had originally been engraved "boom baby", but it turned out super light so was gone over again with the "boom boom". You can still barely see the previous engraving if you look really hard, you can kind of see it in the close up picture because of the flash.
$500 shipped takes it, not interested in trades, located in Pueblo, Colorado.