Something doesn't compute. I read Cruz used a S&W AR-15 -- that's a "high quality" implementation.
I have not read anthing about the ammo he used. But, never in my experience has ammo "broken apart", when using an AR.
This is bona fide "crap" reporting.
Then again, the gist of the story was that he didn't use high capacity magazines so banning them would have done zero against such as him....that's the only part that needs to be accurate to make the context of the story relevant.