The noose tightened around Lee Harvey Oswald yesterday with expert testimony tracing the paths of the bullets that struck President Kennedy and Texas Gov. John Connally to Oswald's alleged perch in the Texas School Book Depository.

Unlike the Warren Commission, which assumed at the outset that the shots came from the building, the House Assassinations Committee said it ordered a study that began with the entry wounds in the two men and the positions in which they were sitting just before they were hit.

After outlining the laborious task, Tom Canning, a specialist in flight trajectories for the National Aeronautics and Space Administration, said he was "confident" that the same bullet that hit Kennedy high in the back also wounded Connally after passing through the president's throat.

Plotting the course of that so-called "magic bullet" and a subsequent shot that smashed through Kennedy's skull, Canning drew a series of three tightening concentric circles from which the shots could have come around the upper floor windows of the book depository.

The biggest circle - really an ellipse - encompassed parts of the fourth through seventh floors and the roof of the building. The smallest circle zeroed in on the sixth floor window where Oswald was said to have set up a "sniper's nest."

Cannng emphasized that this was where the evidence took him.

"To the best of my ability," he told the committee, "I put myself in the position of assuming no gun was found and asking where I would look."

Under questioning by Reps. Christopher Dodd (D-Conn.) and Floyd Fithian (D-Ind), Canning said he had allowed for margins of error in drawing his telltale circles, but conceded the possibility of wider miscalculations. If such mistakes were made, he said, the circles would simply grow bigger, perhaps even including part of an adjacent building yet never eliminating the book depository.

The committee's chief counsel, G. Robert Blakey, reminded the members that other evidence pointed only to the book depository. Neuton activation tests of fragments of lead from Kennedy's brain, Connally's wrist and the floor of the presidential limousine, Blakey pointed out, showed they came from two Mannlicher-Carcano bullets linked to Oswald's rifle. Three spent cartridge cases were found on the floor behind the sixth-floor window. Oswald's Mannlicher-Carcano was found near the staircase.

The Warren Commission concluded that three bullets were fired, one missing the limousine, another (the so-called "magic bullet") hitting both Kennedy was hit from behind at the shot tearing into the president's skull.

In support of the single-bullet theory for the body wounds the two men sustained, Canning said that once Kennedy was hit from behind at the spot pinpointed by medical experts, "it seems inevitable that the governor would be hit." He said the bullet "could not have missed Gov. Connally" unless it were substantially deflected.

"Are you positive?" Rep. Samuel Devine (R-Ohio) asked the NASA engineer.

"'Positive'" is a strong word," Canning demurred. He repeated that he was "confident."

Canning was sitting in a jumpseat in front of the president in the limousine, but closer to the center of the car than Kennedy, according to a study of the photographic evidence. A panel of photo scientists assembled by the House committee agreed 15 to 1 that "the men were sitting in a position consistent with the single bullet theory."

A spokesman for that panel, Calvin McCamy, a former chief of image optics and photography for the National Bureau of Standards, reported that the Zapruder film of the assassination also shows signs of distress on Connally's part sooner than generally supposed.

Playing the film at varying speeds, McCanny pointed out that Connally "seems to be frowning" immediately after the limousine emerges from behind a freeway sign. Connally then turns around, his mouth opening and cheeks puffing up, McCanny noted.

The panel also pointed out that Connally, who said he heard the first shot, seems to be looking around sharply in response to the noise, before the car disappeared from Zapruder's sight behind the freeway sign. At that point, McCamy observed, Kennedy was still "happily waving to the crowd."

The House hearings will continue today with evidence concerning Oswald. His widow, Marina, is expected to be the first witness. Meanwhile, the full House is scheduled to consider a controversial $790,000 request to carry the inquiry through the end of the year. The House Administration Committee recommended the supplemental funding last week by a narrow vote, 9 to 8. It almost died on a 9 to 9 tie, but a "no" cast in the form of a proxy for Rep. Frank Annunzi (D-Ill.) was withdrawn by Rep. John H. Dent (D-Pa.) before the ballots were officially added up.