Several years ago after the AW ban faded into the sunset, I acquired a BCI Defense stripped lower receiver from Chris at Federal Firearms. His price was so low I grabbed a pair of them for whatever the future might hold. Through judicious horse trading, I had procured many other parts to bring another AR-15 into being. One of the parts on hand was the last of a group of USGI M16A2Â barrel assemblies that I had gotten out of Aberdeen Proving Ground in the 1990s. The camouflage painted buttstock assembly and handguards came from Mary’s AR-15 that I had since updated to a collapsible stock and set of quad rails. The flattop upper was purchased for next to nothing. The detachable rear sight/carrying handle was military surplus that I got for a favor. Up until recently scoring the upper receiver, I had assembled the lower and set it aside for forseeable future.
The most difficult thing with building an AR is installing the barrel. Difficult in that it takes five to ten minutes to do!
Barrel installation is complete and the gas tube is pinned in place.
With the M16A2 handguards in place, the rifle is starting to come together.
The surplus rear sight/carrying handle is cosmetically rough but mechanically good to go.
Bringing everything together.
The rifle is now basically complete save for acquiring a bolt carrier group and a charging handle. With only around $100.00 out of pocket so far, I know that I will be able to strike a deal with one of my cohorts!
Myopicvisionary 
John,
Say what you will but the with the correct ammunition and a Norwegian sling set up they do not make a bad CMP/NRA starter rifle, as is (though as one ages going to a smaller rear aperture will help a lot).
Oh the thought of it eventually being used for Service Rifle has crossed my mind!