Blue chips made a breathtaking recovery yesterday with a record jump of 337.17 points fueled by bargain hunting during a rollercoaster session.The Dow Jones Industrial Average rose 337.17 points to close at 7,498.32 after plunging below the 7,000-point threshold for the first time since May. On Monday, the Dow experienced its biggest points drop ever, shedding 554.26 points in a shortened session.Volume rose to a record 1.2 billion shares during a session that saw more than three million shares per minute change hands in the last half-hour of trading.The heavy trading triggered technical difficulties for computers and brokers, traders on the floor said.A hunt for bargains and the triggering of buy orders when the Dow dipped below 7,000 was behind the Dow's rally. The longterm attitude of many investors who did not panic also helped the market.