Washington — In a hard-won victory for the most powerful lobby known to Congress, the House of Representatives has solidly voted significantly to relax the nation's gun-control laws. If -- as expected -- the Senate clears the bill passed Thursday and President Reagan signs the measure, United States residents will be allowed to transport unloaded, ``not readily accessible'' firearms across state lines and face fewer restrictions on their ability to purchase rifles and shotguns in other states. In addition, it makes it more difficult to prosecute gun dealers who violate restrictions on interstate sales.
But the bill, which passed 292 to 130, retains a ban on the interstate sale of handguns.
And during the somewhat raucous debate on the House floor in the moments before the final vote on the bill, the House leadership unexpectedly forced a voice vote that approved an amendment that bans the future sale and possession of machine guns in the US.
Those two exceptions gave gun-control advocates something to cheer about. ``We're delighted that it passed,'' said Sarah Brady, wife of White House press secretary James Brady, who was shot during during an attempt on President Reagan's life in 1981. Mrs. Brady joined with Handgun Control, a Washington lobbying group, to press for stiffer gun-control laws. The bill ``does weaken the gun-control laws already in existence and we're sorry about that. But banning interstate handgun sales was very important to us,'' she said.
Yet the most avid gun-control supporters in Congress took the amendments in stride, reveling instead in the end of a decade-long struggle to liberalize federal gun laws, a struggle they feel they've won.
``We can live with it,'' said a visibly pleased Rep. Harold L. Volkmer (D) of Missouri, who introduced the basic bill passed yesterday.
Last July, the Senate passed a companion bill that, in addition to the provisions contained in the House bill, also permitted the interstate sale of rifles and handguns.
Thursday's vote rewrites the Gun Control Act of 1968, the cornerstone of the nation's gun laws and the bane of pro-gun forces, who have long said the law places too many unnecessary restrictions on law-abiding gun owners.
But the apparent definitiveness of Thursday's decision belies the intense controversy that has swirled around the measure since its introduction last year.
The vote came only after a final, intense lobbying push spearheaded by the National Rifle Association (NRA). Lawmakers described the effort as one of the most bruising in recent memory. While several prominent police organizations backed the NRA's position, others broke ranks with the association, because they saw a need for stiffer gun-control laws. A letter-writing campaign to constituents of lawmakers who hesitated to support NRA positions was described even by many NRA allies with phrases like ``smear-campaign.''
``I've never seen anything quite like it,'' said Rep. William J. Hughes (D) of New Jersey, sponsor of a bill that would have placed tighter restrictions on firearms use.
He was echoing the public and private observations of many of his colleagues on both sides of the issue.
Many wondered whether the rift with police organizations might erode the NRA's traditional lobbying might on Capitol Hill.
``People are going to start taking hard looks at these votes and realize that not everyone in the US is a member of the NRA,'' Representative Hughes said.
Yet if such erosion is taking place, there was little evidence of it during congressional debate: During seven hours of debate, no one rose to urge gun-control laws stiffer than those already in place. Instead, the discussion swung around the extent to which they should be loosened.
``Are you under the impression that it would be useful for people to come here to do a totally stupid thing?'' asked Rep. Barney Frank (D) of Massachusetts, who voted against the bill, when asked why no one spoke for stiffer gun laws. ``[The NRA] is powerful because there are lots of people who agree with them.''
Rep. John Dingell (D) of Michigan, the powerful chairman of the House Energy and Commerce Committee and member of the NRA's board of directors, said Thursday's vote did not reflect the successful application of strong-arm lobbying by one organization as much as it mirrored the attitudes of the American public. ``Congress is just reflecting the will of the people,'' he said.
But the NRA has been vigilant in trying to ensure that the will of the people, at least as reflected by Congress, has meant the preservation of relatively easy access by ordinary people to firearms.
The 3.1 million-member organization marries might at the ballot box with the lobbying clout of an organization that has one of the largest political-action committees in Washington.