The 2nd amendment is one of the most, if not the most, misconstrued part of our Nation's Constitution. First of all, the Bill of Rights was intended (Original Intent) to restrain ONLY the acts and actions (e.g., "Congress shall make no law ...") of the newly created federal government or to guarantee those subject to its jurisdiction certain rights ("... to have the Assistance of Counsel..."). In 1789 there was no concept of gun control as we conceive of it today. However, there was acknowlegement back then that guns could be misused, so there were some proposed constraints upon them, but those were infrequent and proposed as a function of state laws, not federal. That citizens could keep and bear arms is evident from those provisions of the Constitution which address state militias.

So, in my opinion, the original intent of the 2nd amendment's drafters and ratifiers was to preclude the federal governmetn from constraining the keeping and bearing of typical arms of the day but not cannons. Thus, it is inlikely that they would countenance today's citizens keeping and bearing fully automatic weapons.