Though The 5-String Flamethrower is Rob McCoury's first solo album, he's hardly a newcomer. Indeed, there are only a few banjo players today who have been heard by as many audiences, for as a member of the Grammy award-winning Del McCoury Band and its second-generation alter ego, the Travelin' McCourys, he's a gold-plated member of bluegrass music's royalty. But while he cheerfully confesses that he'd been thinking about it for years - and laughingly adds that it took almost two years from start to finish - Rob was in no hurry to get the job done.