There's no way to squeeze out of the amendment a right to guns independent of militia needs. The amendment means that because a free state needs a militia, the right to guns can't be infringed.
In a famous essay, J. Neil Schulman ran the following sentence by Professor Roy Copperud, who wrote American Usage and Style: The Consensus and was on the usage panel for American Heritage Dictionary:
A well-schooled electorate, being necessary to the security of a free State, the right of the people to keep and read Books, shall not be infringed.
Professor Copperud found no grammatical difference between the Second Amendment and that sentence. Under the anti-gun crowd's logic, only the members of a "well-schooled electorate" could own books, when the plain meaning is quite the opposite; namely, an unfettered right to own books is meant to foster a "well-schooled electorate."