Police launched an armed search for Mark Mileham, 25, following the incident in the centre of Leeds late one night.
Mileham was riding his mountain bike in Great George Street when his path was blocked by two young men, Leeds Crown Court was told. He dismounted, drew a black metal handgun from a holster on his hip and held it to the forehead of one of the men.
He then calmly rode off, said Colin Harvey, prosecuting, but was trailed across the city centre after a motorist saw the incident shortly before midnight in January last year.
The witness, a doctor, contacted police on his mobile phone and gave them a running commentary about Mileham's movements until he lost sight of him.
Arrest
But CCTV security cameras were activated and tracked him to the main bus station off The Headrow.
A police rapid response and firearms unit were sent to the scene and arrested him. Officers seized the weapon, a replica Beretta pistol powered by a gas cylinder.
Mileham, of Boldmere Road, Halton, Leeds, was jailed for a total of three years, nine months after he admitted unlawful possession of the firearm and possession of the weapon with intent to cause fear of violence.
Passing sentence, Judge Alistair McCallum said: "The increase in the carrying of handguns, especially in this city and Bradford, has increased so substantially now that one is no longer surprised when people are being shot."
He said that 10 years ago guns on the street were something that would only have been read about in American novels.
Mr Harvey said the incident was witnessed by Dr Alistair Drake. The two men who were threatened and were in their early 20s, had never come forward but the doctor told the court how he saw the incident as he drove past in his car.
"I thought they were in danger of getting shot," he said.
Mileham claimed he had got the weapon from a friend to protect himself after receiving threats on the estate where he lived.
He denied having "paranoid feelings" or putting the gun to the forehead of one of the two men but admitted he was "stupid" when he pulled out the gun from the holster on his hip pocket.
Mr Craig Hassall, for Mileham, said the gun could not be fired at the time because there was no gas cylinder in the weapon and he had no ammunition.