President Reagan has dropped his support for Deputy U.S. Solicitor General Andrew L. Frey as a nominee for a judgeship on the D.C. Court of Appeals in the face of heavy pressure from Senate conservatives, gun owners and antiabortionists. The decision not to resubmit Frey's name to the Senate for confirmation is the first time in memory a president has reversed himself on a selection for the city's courts. Frey, the government's chief advocate on criminal matters before the Supreme Court, was nominated for the local appeals seat last July but ran into mounting criticism when it was revealed that he is a member of organizations that support abortion and gun control. Thirteen Republican senators -- including Jesse Helms of North Carolina and Paul S. Trible Jr. of Virginia -- recently wrote the president saying they would have "no choice but to oppose" the nomination because Frey's affiliations do not concur with party policy. Some local officials said the White House decision to drop Frey, a career Justice Department employe, violates the spirit of the city's merit system of selecting judges. They described the lobbying efforts of some congressmen as a blow to D.C. home rule. "It's a terrible precedent and a regrettable one," said Frederick B. Abramson, president of the D.C. Bar and former chairman of the D.C. Judicial Nominations Commission, which recommended Frey to the president as one of three possible choices. "I think it's unfortunate and regrettable that a candidate is not selected because of some private action he's taken, which in my mind doesn't relate in any way to his ability to be on that court," Abramson said. The White House announced yesterday that Reagan intends to nominate a second candidate chosen by the commission, John Montague Steadman, 54, a professor at Georgetown University Law Center. According to sources, Frey did not withdraw his name from consideration, but it had become clear to administration officials involved in the selection process that he would not be able to overcome opposition in the Senate. "The judgment was that he would not be confirmed," said one source. "There's enough intensity of opposition from enough key people to block his nomination." Frey yesterday confirmed that he had not withdrawn, but he refused to discuss it further. "I don't think I have any comment," he said. Frey's nomination was submitted to the Senate nearly seven months ago but was not voted on before Congress adjourned for the November elections. Until yesterday it was uncertain whether the White House would resubmit his name. Opposition came primarily as a result of Frey's membership in such groups as Planned Parenthood, the National Abortion Rights Action League and the National Coalition to Ban Handguns. But some GOP congressmen also were outraged that Frey had made campaign contributions totaling $150 to Democratic candidates challenging Sen. Orrin G. Hatch (R-Utah) and Helms. A letter to Reagan dated March 13 outlined the objections of the 13 conversative GOP senators. "We are persuaded that Mr. Frey's own political and judicial philosophy is very much at odds with your own philosphy and the public positions you have taken," they said. The GOP platform, they said, "clearly expressed positions opposite to Mr. Frey's conduct on these issues. There could well be other points where he will be at significant cross-purposes to the philosophy that we mutually share." The letter was signed by Helms, Trible, Jeremiah Denton (R-Ala.), John P. East (R-N.C.), Steve Symms (R-Idaho), James A. McClure (R-Idaho), Paula Hawkins (R-Fla.), James Abdnor (R-S.D.), Robert W. Kasten Jr. (R-Wis.), Don Nickles (R-Okla.), Malcolm Wallop (R-Wyo.) and Phil Gramm (R-Tex.). Frey earlier had explained the apparent contradiction in advocating the administration's conservative positions on criminal matters while maintaining memberships in liberal social groups by saying he does not share the administration's views on all issues. "What I do as an advocate is as a lawyer representing a client," he said. "My client happens to be the U.S. government. It would be a mistake to assume that a lawyer always agrees with his client's positions."