At the time, "militia" simply meant "the set of all people who keep arms and train with them" and "well-regulated" meant "which trains regularly". In your defense, "infringed" meant something closer to "voided" than "in any way diminished" (the latter being how we use it today).
So, put into modern terminology, the Second Amendment would probably read,
"Given that it's necessary for enough people to be competent in firearm use to secure the liberty of the populace, the right of people to keep and bear arms shall not be eliminated."
Does a six-day waiting period eliminate the RTKBA? Probably not. Does a background check eliminate the RTKBA? Probably not.