Why the fuck does it matter?
The weapon sold to civilians is not the same fucking gun as the m16 or m4, by many factors and specification.
What's your fucking point?
You are simply wrong. The ONLY differences between Colt AR15/M16/M4 are minor features (barrel length, stock configuration, sights) and the fact that civilian versions do not have burst fire/full auto.
They are all mil-spec, there is no difference in metallurgy or quality.
But feel free to keep embarrassing yourself, it's quite hilarious.
HAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHA! You are a moron.
Here's a hint: An M16 costs about $1300.00. You can pick up a very nice AR15 for about $500.00 Ponder that and see if you can figure out why.