There's a quite famous instance of a Florida gun shop owner defending his store using multiple full-auto weapons. No charges were pressed, as I recall, or at least none stuck. He did kill one of the BGs who tried to run him down with a car.
Harry Beckwith. He passed away about 5 years ago but the new owners of his shop kept his name on it. All thuis occurred just outside of Gainesville in Alachua Fl, one of the most liberal and far left regions in the state. No charges were filed or reportedly even considered.
ALOT of old school deputies hung out there frequently and made frequent use of his indoor range. being friendly with the cops is good insurance.