Azelle Rodney, 24, was killed ''instantly'' when Met officers carried out a ''hard stop'' on a VW Golf in Edgware, north London, on April 30 2005.
Police thought the group in the car - Mr Rodney and two other men, Wesley Lovell and Frank Graham - were on their way to commit an armed robbery linked to drugs.
Ashley Underwood QC told the inquiry into Mr Rodney's death that the officer who shot him, known only as E7, was in the front passenger seat of an unmarked police car that stopped level with the driver's side back window on the Golf.
He said: ''Within less than a second of the car containing the officer coming to a halt, he opened fire with a carbine.
''He fired eight shots rapidly. Of these, six shots hit Mr Rodney. He was killed more or less instantly.''
An inquiry is being held into Mr Rodney's death instead of an inquest because of sensitive areas of evidence that would have to remain secret from a coroner.
It is the first time that this kind of inquiry has been held to look into a police shooting.
Mr Underwood played a video recording of the hard stop captured by another officer, named as E12, which showed a convoy of unmarked police cars driving through residential streets.
As the Golf was brought to a halt, shots could be heard but the shooting itself could not be seen.
Three guns were found in the car, but there are questions over exactly where they were at the time of the shooting, Mr Underwood said.
When a ballistics expert came to the scene they found a Colt .45 calibre pistol on the driver's side of the back seat, partly covered by plastic.
It was incapable of firing - work to get it functioning again after being deactivated had failed - and was not loaded, although three rounds of suitable ammunition were found in a plastic bag in the footwell.
There were two other guns in a rucksack in the back footwell - a Baikal pistol wrapped in a scarf that was loaded but its safety catch was on, and another that looked like a car key fob that was wrapped in a glove. It was loaded and the safety was off.
Lovell and Graham were arrested and later admitted possession of firearms.