Hello all,

I was just poking around the fail zero web page. I noticed that they offered ar-15 parts kits and also M-16/4 parts kits. these kits start with the BCG, and a hammer, them progress to adding a stripped upper.

My question is not with the fail zero products. My question is with the AR parts kit versus the m-16 parts kit. Are these items not the same for both (essentially the same) weapons? If they differ, what does the official m4 or m-16 have over the AR?
Minus the fire control group, obviously... wait, did I just answer my own question?

please help me become more knowledgeable