Originally Posted by Crunchmeister
Then if you got a new 1.2 version, it should be metal. I stand corrected. Up until now, all their guns had nylon uppers.
Easy way to test - pull out the rear body pin and crack the reciever open. Use a tool to lightly scratch the finish inside the upper receiver. You'll be able to tell if it's paint on metal, or nylon.
I have one of the first run Combat Machine M16A3's and my upper is metal. Maybe it was only the M4's?