Barr is Either In or Out After Today Rep. Bob Barr faces his toughest political battle today in a primary election. Barr's facing another Republican incumbent every bit as conservative as he is. His opponent, Rep. John Linder. The two men are facing each other for their party's nomination in a new congressional district, drawn by Georgia's Democratic Legislature. The winner of today's primary is virtually assured of election in the fall. The loser will depart Congress at a time when his party, with only a six-vote House majority, is desperate to keep every seat. Barr has drawn ridicule for a $30 million lawsuit he filed against Bill Clinton, Democratic consultant James Carville and Hustler publisher Larry Flynt. The suit charged that they invaded his privacy, and it sought damages for emotional distress during Clinton's impeachment fight in which Barr was one of 13 House members who presented a case against Clinton. Linder says that ''adds to the chuckle factor'' of the race. A bigger chuckle though might be the fact that one of Barr's biggest supporters is Alzheimer's Poster Boy Charlton Heston, the actor and president of the National Rifle Association. Barr, a gun rights champion, was embarrassed when an antique pistol he was being shown at a fundraising event accidentally fired. No one was injured.On his behalf,I pr,should add Barr has gone on record as moving to revoke the order prohibiting assassinations. He would make a pretty good APster candidate.