Citizen Snips said:
A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed.
This means that we should be able to form a militia when necessary, but also that our individual right to own a firearm can not be infringed upon. The Supreme Court has sided with this time and time again.
It is worth bearing in mind that much of the US Constitution is lifted from the Bill of Rights 1689, including the right to bear arms.
Most of the Act is an attempt to redress the actions of the previous (Catholic) monarch, James II who "by the assistance of divers evil counsellors, judges and ministers employed by him, did endeavour to subvert and extirpate the Protestant religion and the laws and liberties of this kingdom" - so it's a totally unbiased piece of legislation, as you might imagine...
Anyway, that's why the act states
"That the subjects which are Protestants may have arms for their defence suitable to their conditions and as allowed by law"
(which in effect meant "Gentry get to carry weapons, Peasants don't")
The key point is really that the right to bear arms is 'as appropriate'; so if you live in the middle of nowhere, then you probably need weaponry capable of taking down a bear or a dragon, or whatever wild animals wander about in those bits of the US.
If you live in a city, it's not
really appropriate to carry heavy artillery, guns or swords (all of which might make you
feel safer, but so would a blanky).
(The 'armed & well-regulated militia' bit is lifted from a related act, and is a provision specifically to prevent the King sending peasantry into battle unarmed (not that English monarchs were ever complete and total
bastards or anything))