For several years the Reagan administration has tried with uncertain success to eliminate liberal groups from eligibility for funding by the Combined Federal Campaign, the annual $120 million charity drive among federal government employes.

The money, officials say, should go only to such "traditional" charities as the American Heart Association rather than the likes of Planned Parenthood and the NAACP Legal Defense Fund.

Nevertheless, this year's list of eligible "health and welfare" charities approved by the Office of Personnel Management includes subsidiaries of the National Rifle Association and the antiunion National Right to Work Committee, as well as two nonprofit law firms that represent conservative causes.

OPM spokesman Barry Shapiro said the agency had included on the list "anybody who could make a case that they were charitable, tax exempt and that their work contributes to public health or welfare."

The Firearms Civil Rights Legal Defense Fund, whose street address is the same as the side entrance to the National Rifle Association headquarters here, is one of the charities listed this year.

NRA general counsel Mike McCabe, who handles the administrative details of the fund, said phone calls and designated contributions are already coming in as a result of the listing.

The NRA set up the fund about five years ago to "protect people's civil rights and liberties," McCabe said. "We represent people who have been improperly handled civilly or criminally in the context of firearms laws."

McCabe laughed and said that "it does seem a bit incongruous" to see a subsidiary of the NRA, one of the nation's most powerful lobbying groups, on a list of charities. He said he did not realize that the fund might be eligible for charitable contributions until he read about administration efforts to get rid of liberal groups.

"I guess you could call it our day in the sun," he said. "We didn't make the rules, but when we realized we had a legal right to participate , we proceeded to do so."

Also listed this year is the National Right to Work Legal Defense Fund. Spokesman Clayton Roberts said the fund qualifies as a "health and welfare" charity because it "is a legal aid group giving assistance to individual employes who are victimized by compulsory unionism."

The list of recipient charities also includes the Washington Legal Foundation and the Capital Legal Foundation, two conservative public-interest law firms. Spokesmen did not return calls asking for comment.

The Combined Federal Campaign, collecting from some 4 million civilian and military employes, is patterned after United Way solicitations from nongovernment employes.

This year's CFC brochure lists 563 organizations -- many of them also eligible for United Way funding -- that employes can designate as recipients of their contributions. Employes also can write in the name of any other tax-exempt "health or welfare charity" of their choosing. Undesignated contributions are distributed according to a formula set up by United Way.

The CFC brochure offers no description of the organizations and no indication of their purpose, and even their titles are sometimes vague or confusing.

For example, a spokesman for the Jamestown Foundation, a listed recipient, says it is a "nonprofit group that assists high-level Soviet defectors." The Shoe and Rubber Fund, D.C. Congress of Parents and Teachers, provides shoes and rubber rain boots to poor children.

In a victory for the Reagan administration, the Supreme Court ruled last July in a case started by the NAACP Legal Defense Fund that political advocacy groups may be excluded from the CFC list of recipients. Former solicitor general Rex E. Lee told the court the restrictions were needed to prevent the drive from becoming a free-for-all for "universities, opera guilds and animal welfare groups."

Although it sided with the administration, the court sent the case back to U.S. District Court Judge Joyce Hens Green, who is expected to decide soon whether the government improperly tried to exclude groups for political reasons.

OPM Director Constance J. Horner said in August that she will change CFC eligibility rules next year to exclude legal defense funds and lobbying groups. Under those rules, both the Firearms Civil Rights Legal Defense Fund and the NAACP Legal Defense Fund would be disqualified.