Shane Williams, 22, a factory worker who had told his teenage girlfriend he was going to 'do' a cabbie, was convicted of murder at Truro Crown Court. He showed no emotion as Mr Justice Auld sentenced him.
On the night of the killing, Williams, of Furze Hill, Bodmin, called the town's Ansom Cabs firm and asked to be taken to Helland on Bodmin Moor via back lanes.
On a deserted road, Williams asked the driver Roger Dale to stop. He then assembled a shotgun, loaded it, pointed it at Mr Dale, 45, and asked if he had any money. When he was told no, he blasted Mr Dale in the face, Charles Barton QC, for the prosecution, said.
Williams then dragged Mr Dale's body from the taxi and searched him. Although Mr Dale had pounds 30 on him, he did not find it. He fled the scene, hid the gun barrel and returned to the home of his girlfriend, Tanya Andrews, 17, with the rest of the weapon, telling her what he had done.
The jury heard that Williams had told Ms Andrews the day before the shooting he was going to 'do' a cabbie.
Williams, described in court as immature and 'not very bright', had said that he intended to frighten but not injure Mr Dale. He said the gun went off accidentally - caused by a 'twinge' when his body shook and shivered.
However, a firearms expert, Stephen Nicklin, told the jury the murder weapon was not prone to accidental discharge.