The three men were allegedly killed in Essex over a row about a consignment of poor quality cannabis. They were lured to their death by a bogus promise of a major new cocaine deal.
Following the execution, one of the killers likened himself to the "angel of death", the Old Bailey court was told.
The accused murderers, Michael Steele, 55, and Jack Whomes, 36, were driven away at high speed from the shootings, allegedly laughing at their actions in shooting the men in the head as the waited in a Land Rover on a snowy night in December 1995.
Steele "said he felt a bit like the angel of death - he had done everyone a favour and got rid of the sort of people you would not want around", said Andrew Munday, QC, prosecuting.
Steele, from Clacton, Essex, and Whomes, from Brockford, Suffolk, wore surgical gloves, overalls and Wellington boots for the murders at point blank range and afterwards were splattered with blood, according to counsel.
The getaway driver for the murderers was another criminal called Darren Nicholls, 31, who later told police about the incident, the jury heard. Nicholls, from Braintree, Essex, will be a major prosecution witness at the trial.
Patrick Tate, 37, Anthony Tucker, 38 and Craig Rolfe, 26, all from Essex, were killed in Rettendon, Essex.
Whomes and Steele have denied murdering the three men. They - and a third man, Peter Corry, 45, from Clacton - also deny conspiring to import cannabis in late 1995.
Steele believed that Mr Tate had threatened him over an earlier shipment of poor quality cannabis and decided with Whomes to eliminate the threat, the prosecution has alleged.
Steele marvelled at the way his partner had acted, according to prosecution. "He said he was a cold-blooded bastard - his partner, Jack Whomes - because as soon as he got out of the vehicle he put shots into each of their heads within a matter of moments.
"He said it was a natural act - almost as if he was doing something else. It was emotionless." he said
Mundy told the jury: "He said that he, Steele, had shot one of the deceased with both barrels because that person had moved. He said he had reloaded and shot the other two and the gun had fallen apart.
The case continues.