Regulated as defined by Miriam-Webster; Control or supervise by means of rules and regulations.
That regulation was re-affirmed in the 2008 Supreme court decision DC v Heller where it was stated, "the right [to bear arms] is not unlimited. It is not a right to keep and carry any weapon whatsoever in any manner whatsoever and for whatever purpose".
The 2nd amendment was not intended to guarantee your right to stockpile obscene numbers of dangerous assault weapons and deadly ammunition. It's not there for you to satisfy your perverse need to wield power over your adversaries. It's not intended for you to fantasise about your Tea Party militia overthrowing "Tyrant" Obama.
The more the NRA and pro-gun advocates try to bully the rest of us with their irrational arguments, while putting our society and our children at risk of death and injury, the more it becomes apparent that gun regulation is necessary.