AR-15/XM-15 fire is not rapid, unless someone has modified the weapon to full auto or a special grip has been added to the weapon to allow for bump firing.
This is an AR being fired:
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link to www.youtube.com]
But many witnesses described the gunfire as "rapid." Gene Rosen described the sounds using the words "Pop-pop-pop-pop-pop," and he said them rapidly. He said the noise even stood out because it was so rapid, because if it were coming from a hunter, he would consider that an obnoxious way of hunting.
In Kaitlin Roig's recent interviews, she (now) describes the first shots she heard as "rapid gunfire."
I find it interesting that in this early report, Roig had stated she felt exposed because of her many large windows.
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link to www.youtube.com]
While this is understandable, it is strange for a teacher who has just heard gunfire right out her front door to be focusing her attention on windows in the opposite direction of the threat. If in fact one of her large windows had just been shattered however, as one student said, it makes more sense for her to be focusing on a threat from the windows.
Yes, little kids can become confused, but most little kids know the difference between a window shattering vs. nothing happening. Adding to the credibility of the windows shattering is the fact that other early media reports stated they had shattered, and photographs from that day and afterward show broken windows, and then boarded up windows.