For one thing, you will not find any at you local gun shops. You will find semi-automatic rifles that look like assault weapons. But that is all. While they look like an assault weapon, they do not function like an assault weapon.
The rifles on the civilian market are only semi-automatics. This means that you can only fire one round per trigger pull. You have only two functions, safe and semi.
A true assault weapon has a third function, burst or auto. Burst you are limited to three rounds per trigger pull. Auto means it will keep firing until you either release the trigger or the magazine is empty which ever comes first.
So much "reporting" today doesn't understand these most important differences. Or they do, but ignore them to slant the story against guns. Either way it destroys the credibility of the story.
I served for 21+ years between active Air Force and Michigan Army Guard. I earned expert qualification with the M-16 rifle in both the Air Force and Guard.