"Well Regulated" meant well functioning... as in a "well-regulated" clock.
I know it's an unpopular idea, but reading what the actual founders had to say about what they put in the document might be in order. If one does, and then reads the 2nd Amendment in modern parlance, the words look like this:
*Since a group of able-bodied men well trained to act in an orderly military fashion is required for the security of a country free from despotism, the inviolate and natural freedom of every individual to own, possess, and employ the weapons of warfare shall not be abridged by the federal government.*