Here in AZ I think (hope) there would be enough armed citizens shooting back that it would be a short and one sided exchange.
It would be almost exclusively hand guns from the good guys.
Who knows what the bad guys would have.
And here in NJ, it'd be a bloodbath until the cops showed up 15 years later, because Guvy Whorezine doesn't trust his subjects to be armed and protect themselves. That's what the po-po be for......../sarcasm