Richard B. (Hook) Traylor, a nationally recognized gun expert whose Woodbridge home was severely damaged in a gunpowder explosion last year, was convicted by a federal jury yesterday of four firearms violations.

Traylor, a former District of Columbia policeman who worked for the Drug Enforcement Administration at the time of the explosion, was found guilty of two counts of receiving guns stolen from law enforcement agencies, possessing an unregistered Thompson submachine gun and two other weapons and owning a submachine gun with an obiliterated serial number. He was acquitted of three other related weapons charges as the jury ended more six hours of deliberations.

District Judge J. Calvitt Clarke set his sentencing for May 21 in Alexandria. The 53-year-old Traylor faces a maximum of 35 years in prison and a $35,000 fine.

Prosecutors had dropped one charge against the gray-haired Traylor before his trial began Monday, and dropped two other charges before the case went to the jury yesterday. He had been indicated on all 10 counts Feb. 28.

Federal officials discovered the cache of 119 weapons at Traylor's Northern Virginia home after gunpowder and ammunition he kept in the house exploded on May 14, 1979, knocking off one end of his four-bedroom home.

Traylor received second-degree burns over 30 percent of his body in the blast, which led to his dismissal from a $19,263-a-year DEA job 11 days later.Law officers claimed they had found missing government weapons at his home.

The jury in Alexandria found Traylor guilty of having six guns that were stolen from the federal drug enforcement agency and 15 others said to have been taken from District police. Traylor was not accused of having stolen any of the weapons.

He had testified in his defense that the DEA guns mysteriously had appeared in a camper he owned. His lawyer, Jack B. Stevens, had argued that Traylor had "implicit or explicit authority" to hold the guns because he was a gun instructor for the agency.

Traylor claimed that he had purchased the D.C. police guns from soldiers who acquired them after they were discarded following a storeroom fire at police headquarters on Jan. 12, 1978.