CONCORD, N.H., FEB. 3 -- Vice President Bush, running a carefully choreographed campaign for president, came prepared for the Gun Owners of New Hampshire. He brought a gun.

It was a 5.5-ounce, five-shot, .22-cal. pistol that Bush pulled from his suit pocket at the gun owners' forum for the presidential candidates here Tuesday night. The weapon was an example of "plastic guns" that can evade metal detectors. Bush had been given the tiny weapon by the Secret Service, and, holding it aloft, he warned the gun owners that it could "kill the pilot of an airplane."

The audience was hushed as Bush urged the gun owners to compromise with police groups on legislation to outlaw such guns. While Bush didn't offer any specific compromise and vowed to oppose pending legislation to outlaw plastic guns, he said, "My proposal is we sit down . . . and work it out."

Fearing a negative reaction to even a mild disagreement with the gun owners group, Bush campaign workers then quickly fanned out through the hall distributing copies of an endorsement of Bush written that day by Sen. James A. McClure (R-Idaho), a leading opponent of gun control, and another from Ray Scott, president of the 500,000-member Bass Anglers Sportsman Society.

The episode was another demonstration of the deliberate, calculated campaign Bush has waged in recent months in a struggle to defend his place as national front-runner for the Republican presidential nomination. According to his political strategists and others, Bush has attempted to plan his every move, striving to avoid mistakes that could erode his lead, rather than break new ground on major issues or outline an agenda that would take the country in a new direction -- a goal Bush explicitly rejects.

Sources said Bush has set aside, for now, major speeches on the environment, nuclear nonproliferation and defense procurement, all topics that aides say he eventually wants to address. Instead, he has focused heavily on "retail" politics -- handshaking and picture-taking.

Bush has risen above the retail politicking and gained national attention, however, in several aggressive moments that were widely publicized. He has been methodically trying to shake the characterization of him as a "wimp" by cartoonists and others -- a moniker that still hurts and haunts him. His flash of anger last week at CBS News anchorman Dan Rather was one response; this week, he brought famed test pilot Chuck Yeager to his campaign speeches and pointed out that Yeager -- whose daring exploits were chronicled in a best-selling autobiography -- is supporting him.

The vice president's preparations for big events can be painstaking. Before televised debates, for example, he reads briefing material on the issues, then goes through a mock debate rehearsal with aides and others, which is videotaped. Roger Ailes, his media consultant and adviser, then writes a memo of suggestions based on the tape; the Ailes memo is sent to Bush before the debate, according to Bush aides.

Before the Des Moines Register debate, Bush and his aides decided on the vice president's opening gambit -- he would suggest scrapping the entire format and take questions from everyone on the stage about his role in the Iran-contra affair. As it happened, the first target in his sights was the newspaper's editor, James P. Gannon, and Bush took advantage of the opportunity to make the Register an issue -- a popular move among Iowa Republicans.

There was less planning before the confrontation with Rather, but the critical ingredient was suggested by advisers in advance. According to campaign sources, aides proposed that if Rather got nasty, Bush could counter by bringing up the moment last September when Rather, angry over the delay of his news show by the U.S. Open tennis tournament, stormed off the set, leading CBS to broadcast seven minutes of dead air. Bush's reference to that seemed to stun Rather, and was followed by the anchorman's angry outbursts that apparently won public sympathy for Bush.

The vice president's newly aggressive style has extended beyond the Rather interview to others in the news media. He told a Rotary Club questioner here this week that American voters are "smart" and "they don't need a filter" such as the television networks to get their information.

Bush has been more selective than other candidates about his media appearances. He refused to appear on Marvin Kalb's series of televised 60-minute interviews with the candidates -- the only candidate in either party to do so -- saying he could not fit it into his schedule. "It wasn't something we viewed as an opportunity," said one Bush adviser. "There was risk to it."

Several weeks ago, when it suited his purpose of appearing to be responsive on Iran-contra, Bush stood in subfreezing outdoor temperatures to answer reporters' questions for 20 minutes. But he has generally been less accessible to the national news media as the Iowa and New Hampshire voting draws near. Aides often use security as an excuse to keep Bush away from the press or to move reporters out of shouting range. On Tuesday, Bush conducted six interviews with local radio stations by phone from his hotel suite here. But he agreed to take only two questions from reporters covering him. Asked if he would respond to charges from Dole that he had not helped advance the Reagan program, Bush said, "No response to it . . . . The answer is no. Just keep on the high road."

In grappling with the Iran-contra affair -- the most unpredictable element of his campaign for the last five weeks -- Bush and his advisers have attempted to minimize risk and put their stamp on events.

For example, when questions were raised in early January by The Washington Post about whether Bush had given a full accounting of his role in the scandal, Bush went on the offensive, offering to answer all questions. His aides practically begged reporters to submit written questions they could answer. His first lengthy responses, to columnist Mary McGrory, contained a surprising new disclosure that Bush had expressed reservations about the Iran arms sales beyond those previously disclosed about the role of Israel.

Then, within a day or two, Bush privately telephoned former White House chief of staff Donald T. Regan, according to a Regan aide. It could not be learned what Bush said, but Regan subsequently volunteered to corroborate the vice president's account. Bush now repeatedly invokes Regan as a witness to his reservations, which were never mentioned in the congressional investigation or Tower review board probe of the affair.

At the same time, Bush has avoided sitting down for extensive interviews with reporters knowledgeable about details of the Iran-contra affair. Aides say he is still considering requests to do so.

In his effort to run a deliberate, careful campaign, Bush has freely exploited the advantages of incumbency; this week, for example, he plans to use Army helicopters to hopscotch across Iowa in a way that other campaigns can only envy, allowing Bush to hit more media markets in less time than others who must drive.

This month will bring another example of how Bush has worked the machinery of the Reagan administration to his advantage. The president's budget proposals, scheduled for release days after the New Hampshire primary, will feature Bush's proposal for a tax-free college savings bond, White House aides said. After years of proposing cuts in the budget of the Education Department -- and once promising to eliminate it -- President Reagan will ask for additional money for education in the year Bush is campaigning on the slogan that "I want to be the education president."

At this year's budget meeting with the president, Bush spoke up on just one topic, according to a source who was present. The vice president wanted to make sure that the administration kept its commitment to Canada for spending to fight acid rain pollution. The answer was yes, and the White House issued a public statement saying so; if it had not, the issue could have exploded into controversy before the New Hampshire primary.

Bush advisers said that these budget decisions will not by themselves win any primaries, but it would have been far more difficult for the vice president to explain deep cuts in such programs and maintain he was an effective adviser to the president.