GAS FILIBUSTER ENDS AS BYRD OVERRIDES CUSTOMS OF SENATE
8-day-old filibuster against deregulation of natural gas prices ends with unusual maneuver by Sen majority leader Byrd that overrides Sen customs and controversial rulings by Vice Pres Mondale; strategy paves way for quick vote but outrages large numbers of Repubs and Dems; Mondale's role in opposing filibuster is taken as sign that Carter Adm would prefer bill decontrolling gas prices to no bill at all; if Adm succeeds in winning vote for new compromise offered by Sen Jackson or others, much of credit will belong to filibuster leaders Abourezk and Metzenbaum; Carter continues his personal lobbying activities by summoning to White House Sens Quentin N Burdick, Wendell H Ford, John H Chafee and Dennis DeConcini, who are regarded as potential converts to deregulation; highlights of Sen session described; Metzenbaum and Abourezk illus (L)