In the months after the school shooting in Newtown, Conn., some 40 gun control bills were filed in Massachusetts. Many expected a crackdown that would have gone further and faster than other states. Instead, a special commission spent a year carefully crafting an omnibus bill that DeLeo, who is considered a conservative Democrat in Massachusetts, calls “reasonable.”

The Massachusetts bill requires state officials to do better at reporting information to the federal background check database, so anyone found by a court to be mentally ill can’t get a gun, as federal law requires. But the legislation also gives more discretion to police chiefs to deny licenses for shotguns and rifles.

Jack McDevitt, a dean at Northeastern University who chaired the special commission, says local law enforcement officials need that leeway.