Have a friend who is looking for a complete upper with a FSB.  I have built several ARs, but never bought a complete upper, but he wants his complete so he can pop it on his Aero lower and be on his way.

Of course, this is a horrible time to be trying to find anything AR, with a lot of places selling out of just about everything.  That said, any direction I should point him to find what he is looking for?  He wants a 16" barrel, FSB, preferably keymod hand guards and wants to stay in the $500-$600 range at the high end.

Any leads are appreciated!

BCM lightweight would be my top pick and probably within that price range or close.  Without a handguard they usually sell their upper kits for $510 after you add the $70 upgrade to include their BCG and extended latch Charing handle.  Their 16" kit also comes with a BCM Mod 0 compensator which is worth $60-70.  One heck of a deal for the $510 price and you can add whatever handguard, or some even come with handguads for an additional price.  

PSA Premium would be a little cheaper 2nd choice and add whatever handguard is wanted after purchase.  Price is probably around $400-450ish.  BCM is really worth the extra to get the lightweight barrel, extended latch charging handle, the Mod 0 compensator, and their BCG that everyone praises.

Edited to add link - http://www.bravocompanyusa.com/BCM-16-Mid-Length-LIGHT-WEIGHT-Upper-Receiver-p/bcm-urg-mid-16lw.htm

If he was on a budget and wanted to sell some of the extras on that kit he could do fairly well.  For example, sell the Mod 0 comp before firing it for around $60 and buy an A2 FH for $10.  Sell the charging handle for $35-40 and buy a mil-spec one for $15 - I would keep the BCM one for the little price difference and they are very nice.  Sell the BCM BCG to someone as brand new for around $150 and buy a PSA Premium or AIM V2 for $80-100.  Then he would have a total of about $100-125 depending if he kept the charging handle or not off the original price of $510.  So that would make it around $400 with all top quality parts without building anything at all - and leave him the ability to get whatever handguard he wants.  Heck, this is probably even cheaper then you could get a PSA upper for but would involve selling the extra parts and ordering more - which isn't that big of a deal.  Just throwing options out there to think about and to point out how good of a deal the BCM is with the extras.

I just got the BCM Lightweight mentioned above 2-weeks ago.  I couldn't be happier with the quality.  The extra $100 or so was well, well worth it.  Super fast shipping from BCM on the "In-Stock" product.  4-days from order to door step with standard shipping.  The match-up with my Stag stripped lower is perfect.  No gap or slop in it at all.

Instead of keep editing my original post I will throw this out there for something simple if he doesn't want to sell all the extras but keep it under the $600 price.  I would simply do this buy the 16" lightweight which is $439 + $70 for charging handle and BCG then add +$150 for the MI K-Series Key Mod handguard.  This would bring the total up to $660 - $60 over the budget.  Sell the Mod 0 Comp for $60 and get an A2 FH and you are only $10 over budget.  A lightweight barrel is worth considerably more then a gov profile to me.  I love lightweights.

Andro Corp for the win. E-Mail them through here and they'll give you the ARFCOM price. Great uppers. You'll be under $400 complete with BCG/CH with standard handguards.

They do have SLR make some handguards for them if he wants to go up a bit but I think they all use low pro gas blocks. Maybe they could custom make one for him?

Thanks, 2 great options right there.  I'll pass them on.  Open to others.