Gun, the high-concept show that Robert Altman created for ABC starts off with a bang. In the first of six installments following the path of one pearl-handled Colt revolver, a pre-Sopranos James Gandolfini shows a wild intensity that foreshadows Tony’s simmering passion, as a security guard who sends his wife’s lover to sleep with the fishes. The remaining five shows rotate an equally talented cast, with Kirsten Dunst, Carrie Fisher, Edward James Olmos, Rosanna Arquette, and Peter Horton in vignettes ranging from deadly serious to outlandishly satirical. Best of all is Altman blowing away other Gun helmers like Horton and Ted Demme when he steps behind the camera for ”All the President’s Women,” riffing on the war between the sexes. One quibble: a lack of continuity between episodes (it’s never explained how the firearm pops up in the different locales). And with only a gallery of photos, these EXTRAS are firing blanks.