Matthew Ferry, who had been freed under six bail orders by sheriffs at the time, escaped with £233,160 of high-value watches from Laing the Jeweller in Edinburgh’s Frederick Street despite being pursued by the managing director.
Ferry, 24, hijacked a private hire car with its driver and a passenger, forcing the driver to go through red traffic lights to make his escape from the city centre.
A judge told him at the High Court in Edinburgh: “It is clear this must have been terrifying for your victims – the people in the shop and the people in the taxi.”
Lord Glennie pointed out that he had also admitted possession of the prohibited MAC-10 machine gun – a weapon he described as a high-powered, rapid fire gun “clearly deadly if used in anger”.
Armed police later raided the home he shared with his grandmother in Chesser, to find the MAC-10 machine gun alongside the replica pistol.
Officers also seized ammunition for the deadly weapon, and a stash of heroin worth around £50,000.
CCTV footage of the shock raid was played to the High Court showing the moment Ferry turned up at the jewellery shop at opening time with his face masked by a scarf, and his head covered by a hood.
The images show staff opening the doors to Ferry, who pulls a gun from his waist belt and points it at terrified workers who go into the window display to hand over the watches.
Advocate depute Alex Prentice QC said that Ferry repeatedly threatened the shop assistants to put the watches in his rucksack, or he would shoot.
The court heard that Ferry had a string of previous convictions for offences including housebreaking, theft of cars, crimes of violence, possession of weapons including an axe, assault to injury, and misuse of drugs.
Ferry admitted committing the armed robbery, assaulting three staff members at Laing and abducting and assaulting the taxi driver and passenger between Hanover Street and Royston Mains Crescent on 2 March.
He also pleaded guilty to possessing the firearms, ammunition and the class A drugs on 5 March.
All offences were committed while he had six outstanding bail orders.
Lord Glennie told Ferry: “It’s clear from the victim impact statement that it’s had a lasting effect on the taxi driver.”
He added: “It’s a high-powered, automatic firing gun, clearly deadly if used in anger. There’s no excuse for possession.
“Offences of violence of the kind perpetrated by you cannot be tolerated.”
The judge said he would have jailed him for 17 and a half years had it not been for his early guilty plea, reducing the jail time to 13 years.
Ferry’s family shouted “Love you, son” from the public gallery as he was led down to the cells.