An already fractious congressional race in Virginia's 8th District got rougher yesterday when Republican challenger Stan Parris charged Rep. Herb Harris (D-Va.) with violating federal law by using his free mailing priviledges to send out campaign literature.

"I'm angry and appalled by Herb Harris' blatant and brazen attempts to buy his reelection in Congress," said Parris, who is trying to win back the seat he lost in 1974 to Harris, a man he characterized yesterday as "morally dishonest."

After filing a formal complaint with a House ethics committee, Paris called a press conference to explain his accusation that Harris used "more than $60,000 of the taxpayers' funds" to mail 540,000 congressional newsletters that Parris described as "campaign brochures."

Harris called Parris' charges "factually incorrect." The 54-year-old liberal Democrat said all of his newsletters were reviewed, and approved, by a House commission charged with that responsibility.

"This is a desperate attempt to call attention to his sagging campaign," said Jack Sweeney, a spokesman for Harris. "The fact is that Stan knows we've met all the regulations."

Yesterday's clash between Harris and Parris was the latest exchange in a campaign that has been bitterly fought from the start. Harris has accused Parris of being in the pocket of Big Oil. Parris has countered that Harris is weak on national defense and strong on federal spending. The intensity of the campaign has left a third, independent candidate bemused.

"I expected to discuss the issues, not listen to a shouting match," said Deborah Frantz, whose primary issue is the repeal of all U.S. laws regulating marijuana.

Yesterday's controversy centers on newsletter mailings delivered by Harris' congressional office to the House post office. The deadline for delivery of newsletters is 62 days before an election, or in this case, Sept. 3.

Harris said he has receipts that prove his newsletters were delivered under the deadline. Parris complained that they were deliberately held until the last day when a high volume of mail would prevent them from being distributed for as long as three weeks.

"He may not have violated the letter of the law, but he certainly violated the spirit of it," said Parris.

Parris further charged that at least one newsletter was prepared by a private advertising agency, which would violate federal law, and that the design and content of the newsletters were deliberately political.

Asked how the Harris newsletters could have gotten past the House franking commission, Parris said the commission only looked for technical violations and gave just a "cursory glance" to content.

"We do check the content, that's the main thing," countered Jonas Bobelis, a staff member of the franking commission. Bobelis said Harris' newsletters did not violate any of the commission's regulations.

Harris who denied yesterday that any of his newsletters had been prepared by an advertising agency, took advantage of the press attention to repeat his own charge that Parris violated the ethical spirit of his office by removing $3,222.69 in his Congressional stationery fund when he left the 8th District seat in 1974.

Parris answered yesterday that he had put more than that amount of his own money into the account and was only retrieving personal funds.

Harris also countered that in 1974, when their roles were reversed, Parris took advantage of the regulation that allowed congressmen to send free newsletters until just 28 days before an election.

"There isn't any question about it, he was mailing a voluminous amount of newsletters up until 28 days before election," said Harris. Parris said yesterday he could not remember when he mailed things six years ago.

Both men yesterday accused each other of trying to "buy" the district, which covers Alexandria and Prince William, southern Fairfax and northern Stafford counties. Parris said Harris was abusing his free mailing privileges. Harris said Parris and his "Madison Avenue bunch" were blitzing the district with $200,000 worth of "real detergent ad programs."