Thanks for being classic examples of what I was talking about above. You have opted to go with the second part without the context of the first part. Why? I don't know, but "well regulated" was put in for a reason, just like "shall not be infringed." As the OP queried, what does "well regulated" mean? The founding fathers obviously thought it important enough to put it ahead of the part about "shall not be infringed" and so it is in a position as both importance in the statement and as a precondition.
Double Naught, here is where we part company.
The first part of the amendment, is a preamble, or a prefatory clause. Let's examine the words, as understood at the time; from the 1828
Webster's:
PRE''AMBLE, n. [L. proe, before, and ambulo, to go.]
1. Something previous; introduction to a discourse or writing.
2. The introductory part of a statute, which states the reasons and intent of the law.
prefatory: adj. serving as an introduction or preface.
PRE''AMBLE, v.t. To preface; to introduce with previous remarks.
PREF''ATORY, a. Pertaining to a preface; introductory to a book, essay or discourse.
It was, at the time of the founding, a common literary mechanism to justify the statements or statutory language that follows. Is it legally binding? No.
The preamble to the Constitution is just that. A justification for the rest of the document. It carries no legal weight, but is useful by the Courts to determine the origin, scope, and purpose of the Constitution.
Further, consider the language of Art. I section 8, clause 8:
To promote the Progress of Science and useful Arts, by securing for limited Times to Authors and Inventors the exclusive Right to their respective Writings and Discoveries;
The prefatory language,
"To promote the Progress of Science and useful Arts," does not place limits on the Congress to grants of copyrights and patents that only promote Science and the Arts. The Court has held that the Congress itself may declare what is useful to promote science and the arts (citations too numerous to list, but see
here, if interested).
So now we look at the preamble (or prefatory language) of the 2A:
"A well regulated Militia, being necessary to the security of a free State," would place no more inherent restrictions upon the right, as any other constitutional prefatory language. This, I believe, is what the Court in
Heller will hold to, if it is to be consistent with its other decisions on such language (it is well documented in the briefs by and for the respondent).
If my interpretation is correct, then the militia (well regulated or not) is only the start of the right, and not the ends.