The Constitution really says, "The presence of a well-stocked militia being necessary to guarantee a free and prosperous people, the right of the people to keep and carry weapons shall not be infringed."
As long as it's a law abiding citizen, he can have chain-guns, rocket-propelled grenades, heat-seeking missiles, suitcase nukes, Abrahms Tanks, whatever he wants to own, maintain and use to stay safe and free.
Period. That's what the Constitution says.
8^D