You sure about that?

FBI special agent in charge Kevin Rojek said Crooks used an AR-style rifle chambered in 5.56mm, a common caliber for such weapons. Authorities said the weapon was identified and traced using records from a gun dealership that is no longer operating.

If that source doesnt work for you, here’s the president of the United states:

“An AR-15 was used in the shooting of Donald Trump, just as other assault weapons were used to kill so many others, including children."

That’s from the linked article.