Breaking down

It is common practice to break something down into smaller pieces to understand it. When dealing with the written word, this method is most helpful in understanding intent. However, great care must be taken to ensure that the small sub section's interpreted meaning does not conflict with the passage as a whole.

In a similar manner, lets break down the Second Amendment into its parts for complete and accurate translation. Lets see what it means:

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..."
"Well regulated" from 18th Century parlance means that the members of the Militia would be understanding of and capable of the following commands:
- Make ready!
- Take aim!
- Fire!
To "make ready" was to bring the rifle to one's shoulder, and cock the hammer. "Take aim" and "fire" are pretty self-explanatory in modern parlance.

"...militia..."
Any able-bodied person of fighting age. In the 18th Century, it was not uncommon to see people fighting as young as 15 or 16, or as old as age 70+. Generally men fought, but there are numerous recorded instances of women picking up arms, too.
The militia was this group of people.

"...being necessary to the security of a free state,"
The founding fathers did not want a standing Army, as it could be ordered to attack its own citizens. The Militia would more than suffice, as it was basically everybody.

"...the right of the people..."
Clear indication of the intent to recognize individual rights - not a "collective" right, and certainly not a mention of a militia in the sense of the perversion of the word we have today.
Note: as with all other rights - this is not granted by the Constitution, but is recognized by the Constitution as being granted by God and worthy of recognition in an official capacity.

"...to keep..."
To have. To own. To purchase. To sell. To repair. To otherwise engage in normal commerce with.

"...and bear..."
To wear. To carry with one. To have at the ready in the event of need. To otherwise not lock away, but to have at the ready.

"...arms..."
Firearms. Weapons of any sort. This includes ammunition, and other essential elements that allow the arm to function as intended.

This amendment was included because King George III was confiscating munitions (ammo), trying to restrict modern guns of the day, and otherwise similar stuff to the legislation we see being attempted to this day. So the argument that modern guns were not what the founding fathers had in mind is utter and complete bunk - the King wanted to take away the "modern assault weapons" of the late 18th Century!

"...shall not be infringed."
Not prohibited. Not legislated against in any way. This includes permits, background checks, restrictions of any sort. Any legislation that would restrict free commerce or possession of arms is clearly prohibited.