^^^ I agree with JimDandy. This part of Heller
that he quoted immediately above is all we need, right there in front of us. All within one paragraph, Mr. Justice Scalia tells us that the RKBA is an individual right, AND that the right applies to those types of weapons in common use for lawful purposes.
Elsewhere in the very beginning of the Heller
decision, Mr. Justice Scalia refers to the "core lawful purpose of self-defense." (See page 3.)
Link to the decision: http://www.supremecourt.gov/opinions/07pdf/07-290.pdf