For nearly a decade, Colt Defense went without a lobbyist. The legendary gun maker based in West Hartford, Conn., had an exclusive deal to provide combat rifles to the U.S. military and didn't need a hired gun looking out for the company's interests in Washington. Times have changed. After buying more than 700,000 Colt M4 carbines, the Defense Department has started a search for the rifle's successor, giving Colt's competitors the long-awaited chance to break the company's grip on the market. So Colt turned to Roger Smith, a former deputy assistant Navy secretary-turned-lobbyist, to be the company's voice in D.C....