I've never really understood why citizens in the US aren't allowed these items, if the fundamental purpose of the 2nd Amendment is to allow the citizenry to fight tyranny then why aren't the citizens allowed the appropriate arms to do so? How are the laws that allow the US gov to exclude citizens from owning these not 'un-constitutional'? I imagine the answer probably lies somewhere in the "too much risk for accidents or deliberate hostile use" territory.
I hope this isn't inflammatory, not my intention, given what we continue to see re mass shootings, and the gun control proposals that happen afterwards it seems a bit like you have the worst of both worlds.
Put differently, there are enough citizen firearms with enough firepower to facilitate individuals attacking soft targets with horrendous effect but not enough firearms or firepower for civilians to actually have any remotely likely potential of defeating a tyrannical US military (or even police force).