Handgun purchasing laws in Connecticut have resulted in a 40 percent drop in statewide gun deaths, according to a new study out of Johns Hopkins University.

The paper looks at Connecticut's "permit to purchase law," which went into effect in 1995. That law says potential gun buyers must complete a safety course, undergo a background check, and then get a permit before they can purchase a pistol or a revolver.

In the paper, authors compared firearm-homicide rates in Connecticut to those in similar states with no "permit to purchase" laws. Over a nearly ten-year period, they estimated Connecticut's purchasing law resulted in about 300 fewer handgun deaths.

"There's nothing shocking to me in this study. Except for that fact that the numbers are so big," said Senator Chris Murphy. "That even controlling for all of these other possible factors, we have seen a 40 percent reduction in gun homicides in Connecticut."

Now, Murphy, along with Representative Elizabeth Esty and Senator Richard Blumenthal, is co-sponsoring a bill bringing Connecticut's "permit to purchase" idea to other states.

The bill would authorize a grant program at the Department of Justice that would encourage states to establish permit-to-purchase regulations for handguns bought at gun shows and through private sellers.

Murphy said the Johns Hopkins study, which was published in the American Journal of Public Health, is just more evidence that other states need to get on board.