A D.C. Superior Court Jury yesterday convicted two Washington men of shooting an off-duty Secret Service officer to death outside a Northwest Washington bar in January 1980.

Ulysses Jones, 25, and Ricky D. Bryant, 23, were convicted of first-degree murder and armed robbery in connection with the death of George I. Coaxum, 32. Coaxum was shot three times in the early morning of Jan. 11, 1980, outside Chuck's Bar and Grille on Irving Street NW.

According to testimony, Jones and Bryant were both at Chuck's that night and had had a verbal dispute with Coaxum. Assistant U.S. Attorney Harold L. Cushenberry told the jury that at closing time Coaxum walked two women who had been at the bar to their cars and that Jones and Bryant were waiting outside for him.

Cushenberry said Jones and Bryant robbed Coaxum of his wallet and gun, then shot him in the back as he tried to flee.

Defense attorneys Frank Burgess and James Doyle, noting that police had originally charged two other men in connection with Coaxum's death, argued that police were again mistaken when they charged Jones and Bryant in the case.

Jones and Bryant could receive life sentences.

Jones is also awaiting trial in connection with the slaying of Korean merchant Boo Weol Park in December 1979.

Coaxum had worked as a uniformed officer for the Secret Service for 9 1/2 years. He was assigned to the foreign mission division responsible for guarding embassies.