It is clear that the framers of the Constitution were referring to personal weapons. However, this law is anachronistic. Weapons today are much deadlier than they were than when the law was written. The framers of the Constitution would never have allowed people to have machine guns for personal use.
The militia that the Constitution refers to -- the entity that is allowed to keep and bear arms, according to it -- was at the time understood to mean all of civil society. Any person who is not part of the established civil security (police) or national defense (military) organizations would have been considered a part of the militia, and thus permitted to own weapons.