Private Lee Clegg, 25, showed no emotion as the judgment was announced in the Northern Ireland Court of Appeal.
Karen Reilly, 18, was shot dead along with 17-year-old Martin Peake when paratroopers fired on their stolen car in September, 1990.
During the trial Clegg was acquitted of attempting to murder Mr Peake, the driver, but was found guilty of attempting to wound him.
The Lord Chief Justice, Sir Brian Hutton, said yesterday that the firing of a high velocity rifle amounted to the use of lethal force which was grossly disproportionate to any crime that might have been committed by the people in the car.
In those circumstances the force used was clearly unreasonable and Pte Clegg's appeal had to be dismissed.
A second paratrooper, Pte Barry Aindow, 25, who was jailed for seven years for attempting to murder Mr Peake, had his sentence reduced to four years after the Chief Justice substituted a charge of attempted wounding.
During the trial last June the soldiers claimed they opened fire in accordance with the rules laid down in the yellow card issued to soldiers on duty in Northern Ireland.
But Sir Brian said the card had no inherent legal force and it did not follow in every case that opening fire within the terms of the card could be held to constitute reasonable force. 'Therefore we consider it would be desirable for the Army to redraft the yellow card to make it clear that the mere fact that actual injury has been caused does not justify a soldier in opening fire.'
Sir Brian said: 'This court considers . . . that the law would be much fairer if it had been open to the trial judge to have convicted Pte Clegg of the lesser crime of manslaughter. We consider that Parliament should consider a change in the existing law.'
Peter Smith QC, for Clegg, was granted twice the normal 14-day period in which to seek leave to appeal to the House of Lords.Reuse content