History of the AR-15

That is interesting.

But...

Americans have a right to own weapons of war. In the 1800's, every court that ruled on what weapons we have a right to own said so.

Many courts said civilian weapons were not protected (bowie knives etc) but military weapons were, including cannons.

Even US v. Miller admitted this.

I'm not sure what qualifies as the military "adopting" the M16, and the exact date of that occurrence. There was a lot of interbranch controversy over the M16, and the history of the military's transition from the M1 and M14 to the M16 is complicated. Early versions had numerous problems. Nevertheless, the Army did order 85,000 M16A1 rifles in November 1963. The M16 the standard small-arm of all US forces until the end of 1968.