yeah I can see where you're going with the rail uglies... though not my preference, I personally believe the advent of the FF Rail systems made the AR/M series so much more flexible that it is now one of the most versital weapon systems around. Just the optics placement options are worth at least some of the little add on rails. But yeah, that full length hand guard on the 16" upper is a good look and I can see why you're liking it.

Let us know what you come up with on a upper!