That's fine. Every time you lie and say I don't answer your questions this thread will be bumped as evidence you are lying.
I have made my case. You? Not so much.
But here it is in a nutshell. The Colt SP1 AR 15 and the Fairchild Armalite Rifle 15 which became the Colt c601 and later branded the M16 are to separate weapons. One designed for the battlefield, one was not.
And the lowers show that to you. But you know if you answer HONESTLY you will lose. So you dishonestly avoid it.