The man who successfully challenged the D.C. handgun ban before the U.S. Supreme Court filed a second federal lawsuit yesterday, alleging that the District's new gun-registration system is burdensome and continues to unlawfully outlaw most semiautomatic pistols. Dick A. Heller, a 66-year-old security guard who lives on Capitol Hill, and two other plaintiffs allege in the lawsuit that the D.C. government violated the letter and the spirit of the landmark Supreme Court decision, issued June 26, that struck down the District's decades-old handgun ban. The 5 to 4 ruling concluded that the Second Amendment grants individuals the right to possess...