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 is about as unambiguous as one can get when framing a document of governance where the framers are trying to make a clear statement as to the prohibition of acts by the government.
A well-regulated, (governed or directed according to rule)
militia (a body of citizens organized for military service)
being necessary (logically unavoidable)
to the security (freedom from danger)
of a free State (State in this incidence means the States that make up the U.S. as well as the U.S. itself)
The right (the power or privilege to which one is justly entitled)
of the people (the citizens of the United States)
to keep (to retain in one's possession or power)
and bear (to move while holding up and supporting)
arms (a means, as in a weapon, of offense or defense)
shall not (total prohibition against)
be infringed (encroach upon in any way that violates the law or the rights of another).
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.
A well-regulated militia means a well-maintained and armed body of men composed of the common people. George Mason said, "I ask, sir, what is the militia? It is the whole people, except for a few public officials." This Amendment emphasizes that such militias are necessary to secure the freedoms of the people. A free state was considered one in which citizens had inalienable rights, government derived its power from the governed, and the people had the right to alter or abolish the government if it became tyrannical. The right of citizens to keep and bear arms is the guarantee of that free state.
The Founding Fathers of the Constitution knew of the potential evils of having standing armies in times of peace. In free states, the defense of the realm was considered best left to citizens who took up arms only when necessary and who returned to their communities and occupations when the danger passed. They observed that professional soldiers endangered liberty. Standing armies were viewed as instruments of fear. A main danger to a free republic was tyrannical government and the ultimate check on tyrannical government was an armed population.
From the above information we can see how the Third Amendment ties in with the Second Amendment.
"No Soldier shall, in time of peace be quartered in any house, without the consent of the Owner, nor in time of war, but in a manner to be prescribed by law."
But does the term include any and all such objects as might be used for such purpose? If so, on what items is the government allowed to place taxes or any other restriction?
IMHO, and the Court in Miller seemed to take this view, the prefatory phrase of the Second Amendment serves to clarify that the "Arms" protected thereby are those artifacts which could be used effectively as weapons in the context of a well-functioning citizen army.
M-16 clearly included. Glock 19 clearly included. Cane gun, perhaps not.