I have a never fired, just attached to lower, 14.7" M4A1 upper receiver. Permanently attached A2 flash hider to bring it up to 16" (non-NFA). FN-made, CHF/CL upper. 5.56mm. Comes with charging handle and BCG.
Will sell for $500 shipped.
IM is best way to contact me.
edit: New, and improved pictures. Excuse the filthy floor.