A prominent gun control group said yesterday that Rep. Stan Parris (R-Va.), who is seeking reelection, "caved in to the radical gun lobby" by opposing a seven-day waiting period for handgun purchases.

Sarah Brady, chairman of Handgun Control Inc., and Alexandria Sheriff James H. Dunning assailed Parris in a news conference for voting against the "Brady bill" when it was defeated in 1988. The legislation was named for Sarah Brady's husband, Jim, who was seriously wounded in an assassination attempt on President Reagan.

Parris, who represents Northern Virginia's 8th District, is being opposed by Alexandria Mayor James P. Moran Jr., a Democrat. Although Moran's campaign was not involved in yesterday's news conference, Moran supports the Brady bill and has received a $1,000 contribution from Handgun Control's political action committee. Dunning is also a Democrat.

A spokesman for Parris, Mark Strand, said that Parris opposed the bill because of "a difference in approach" to the problem of violent crime. Parris supported plans for a computerized criminal information system that would allow gun dealers to check instantly on the background of potential buyers.

Parris "does feel it's important to keep criminals from purchasing handguns," Strand said. "But you shouldn't throw up prohibitions on honest, law-abiding citizens."

Brady called the plan Parris backed "a pie-in-the-sky scheme" and "a smokescreen promoted by the National Rifle Association to defeat the Brady bill . . . . The system Stan Parris voted for cannot be implemented for several more years and will cost billions of dollars."

Dunning, who listed a dozen police groups that support the Brady bill, said Parris's vote against it "did not represent the people of the 8th District . . . {nor} law enforcement professionals, who risk their lives every day. We deserve better." The Brady bill has been reintroduced and a vote in the House is expected this year. Strand said Parris has not decided how he will vote.

Moran said that he supports both the Brady bill and a ban on the sale of assault weapons, even though he questions whether the stands are good politics. The 8th District includes Alexandria, southern Fairfax County, eastern Prince William County and northern Stafford County. In more rural parts of the district, Moran said, many gun owners oppose all forms of gun control.

"I know it's going to lose us a couple of votes in Prince William and Stafford," Moran said. "And the people who support the Brady bill also tend to support my stands on other issues, so I may not pick up any new votes on the issue. But I think it's the right thing to do."

Brady and Dunning emphasized that the seven-day waiting period would apply only to handguns, not to hunting weapons. But Strand said Parris opposes all waiting periods.