William Johnson struggled for the .357 magnum revolver held only inches from his chest. He watched the gun as it fired seconds later. He saw his shirt tear as the bullet struck. He felt its crushing force. And because the 62-year-old Alexandria deputy sheriff was wearing a bullet-proof vest, he was alive yesterday to help convict the man accused of trying to kill him.

It happened shortly after 4 a.m. Sept. 27 as the 62-year-old Johnson reshackled the wrist of wounded robbery and kidnaping suspect James H. Tinsley, to a bed in Alexandria's Jefferson Memorial Hospital. Tinsley suddenly grabbed Johnson's wrist and lunged for his revolver.

"He was choking me; I was choking him," Johnson told Alexandria Circuit Court Judge Wiley R. Wright yesterday during Tinsley's trial on charges of attempted murder. " . . . I could barely touch the pistol, but I couldn't get a hold of it. Then he pulled [the weapon] so hard, it snapped out of the holster."

Stunned by the bullet, Johnson fled the room after Tinsley grabbed the deputy's keys, he testified. Tinsley then unlocked the shackles on his legs and escaped through a first-floor hospital window.

He was recaptured about three hours later in a wooded area between Van Dorn Street and Shirley Highway, after a police manhunt that disrupted morning rush-hour traffic. Johnson's handgun was found about 15 feet away.

Johnson's testimony was central to the nearly three-hour trial that ended with Wright's finding Tinsley, a 32-year-old Hampton, Va., man, guilty of attempted murder. Wright also found Tinsley guilty on four other counts, including robbery, use of a handgun in the commission of a crime, and escape.

Tinsley, who waived his right to a jury trial, faces a maximum of two life sentences plus 27 years. Sentencing is scheduled for Jan. 11.

Tinsley's attorney, Alfred Swersky, who unsuccessfully tried to get the judge to drop robbery and escape charges against Tinsley, said he plans to appeal the verdicts.

A week before his escape, Tinsley led Alexandria police on a wild chase, wrecking several police cars and the one he was driving, after an attempted robbery of a savings and loan in the Bradlee Shopping Center in northwest Alexandria. Police said Tinsley dragged an elderly bank customer to a car while firing a pistol during the incident.

Before Tinsley was arrested, police said, he shot himself in the leg, which is why he was in the Alexandria hospital. Trial has been set for Dec. 21 on the robbery and kidnaping charges growing out of the alleged attempted bank robbery.

Another key witness in yesterday's trial was Martha P. Smith, who testifed that about 5 a.m. she was leaving for work from her West Braddock Road apartment building near the hospital, when she met a man she identifed as Tinsley kneeling by her car holding something covered with a white hankerchief.

"He said in a low voice, 'Hand me your keys,' " Smith testified. When the man repeated the command and ordered her to go with him, she testified, she ran screaming back to her apartment.

After the guilty verdicts were read, Johnson's wife, Reba, was pleased, but said the ordeal would not soon be forgotten. "It's something you don't just drop and take off like clothes," she said of her husband's experience. "It's something that's part of you."