Maj.Lones Wigger, yesterday challenged his world record equaling air rifle score fired Monday and won another point to give him a new U.S. record-386-one higher than the world mark. Then he added a 375 for a 2-day 761 in the 3-day tounament. Maj.John Foster of Phoenix fired a 380 to lead the field yesterday w/a 759 total that moved him into 2nd place. Maj. Foster led the field w/a 574 in the Standard Rifle event and shaved the 6 point lead compiled by Marine CWO David Boyd to 2 points, 1137 to 1135. Results of yesterday's shooting (July 21): Standard Rifle; CWO David Boyd 567-570 TL 1137 Maj.John Foster 561-574 1135 1Lt.John Writer 554-572 1126 Ladies Standard Rifle; Capt.Margaret Murdock 565-559 TL 1124 Tricia Foster 549-556 1105 Air Rifle; Maj.Lones Wigger 386-375 TL 761 Maj.John Foster 379-380 759 CWO David Boyd 381-369 750