Faxon Firearms makes a really awesome self contained piston driven upper with a quick change barrel system. For the most part their uppers have a 4-8 week lead time but recently they have upped production on one of their most popular models so that they are now in-stock instead of having to wait for them to be built. The model they will be stocking is the ARAK-21 5.56NATO 16″ Medium Profile Barrel in all Black. Obviously they do offer other configurations which you can custom order but if you want immediate delivery, you know what to order. Take a look over at www.FaxonFirearms.com.
In order to expedite delivery to our customers we are beginning to stock a standard ARAK-21® Upper Receiver for immediate delivery. They are black, right hand ejection, 5.56′ 16″ medium profile barrel. http://www.faxonfirearms.com/p/45/stock-arak-21-upper-receiver-one-steel-barrel