After the mass killings in Las Vegas there was a lawyer (?) on TV listing the federal law that stated police were not allowed to have automatic weapons or any other weapon that can cause massive casulties like the military. Does anyone else know about this?
Civilians who can get a Class III licence and afford to pay for a Pre-86 machine gun and NFA tax stamp can own automatic firearms. Police officers are civilians too.
Any weapon can cause mass casualties. A lot of non-weapons can cause mass casualties. We'd have a hard time buying anything from cars to cake knives if they regulated them based on how many people they could kill at a time.
Or do you mean carry automatic weapons while on duty or in uniform? Because that I have no idea about.