On balance, states in the mid-Atlantic and Northeast have stricter gun controls than the rest of the country.

That's according to Jon Vernick, co-director of the Center for Gun Policy and Research at Johns Hopkins University.

"Even Pennsylvania, which is known as a state with a gun culture, requires that all gun sales undergo a background check, not just sales from licensed dealers, as is the case under federal law," said Vernick.

Since the federal ban on assault weapons was allowed to expire in 2004, only about a half-dozen states have implemented their own bans on military-style guns. New Jersey has, while Pennsylvania and Delaware have not.

The Garden State is known nationwide for its strict gun laws, earning high marks from gun control advocates. (The same gun control group graded Pennsylvania and Delaware less favorably.)

"New Jersey also has an interesting law with regard to what are called 'smart guns,' sometimes called 'personalized guns,'" said Vernick. "That is, guns which are designed to fire only for their authorized user."

Vernick says the law, which passed in 2002, is not in effect yet.

It was written to kick in when smart guns were readily available, which back then supporters said would come in a few years.

A few prototypes have been made since then, but gunmakers have largely walked away from the still unproven technology.