LOOK: Buy from JoeBob's The prices are good / they ship fast /
The will help you over the phone or on chat.
They sponsor this site.
I did get a complete 300 BO side charging 16in upper from MidwayUSA for $336
It was an AR-Stoner, Midway guarantees them for one year.
I put my Specwar on it and ripped 10 rounds off. Kept 2 inch group at 50 yds with iron sights
It has a pistol gas system so subsonic's fire just fine.