Jordan Cattell, 22, pointed the weapon at Tony Bangar after entering his store alongside accomplice Lewis Crutchley, 23, on March 24.
In an act of bravery, Mr Bangar – whose family were upstairs – grabbed the barrel of the bolt action shotgun but released the weapon after fearing Cattell would pull the trigger, Wolverhampton Crown Court heard.
Judge Michael Chambers QC said: “Mr Bangar was understandably terrified that he was about to get robbed.”
Earlier that day, Cattell produced the shotgun to a pedestrian after he was unable to get both defendants some cannabis upon request.
Mr Stephen Cadwaladr, defending Cattell, said both defendants were “in drink [that day] and went out together with a 410 [shotgun]” which had been stored in a bag on a canal towpath.
“These men behaved stupidly and criminally together,” he told the court. He said they went out with the “intention of acting tough and taunting people”.
Crutchley, of Aldridge Road, in Perry Barr, was also jailed over a burglary of a Wolverhampton widow’s home in January where her pet dog and necklace bearing her husband’s ashes were stolen. The court heard the victim, who lived on Hall Lane, in Woodcross, had to pay £2,000 to get her dog back but the necklace was never recovered. A quantity of jewellery, an Xbox and iPhone was also stolen.
In total, Crutchley was sentenced to seven years and nine months in prison for both offences after he pleaded guilty to two counts of possessing a firearm with intent to cause fear, possession of a bolt action shotgun and burglary.
The firearms offences earned him four years and the burglary three years and nine months which were ordered to be served consecutively.
Cattell, of no fixed address, was sentenced to six years in prison after he pleaded guilty to two counts of possessing a firearm with intent to cause fear and possession of a shotgun. He also pleaded guilty to possession of a slam gun and possession of shotgun cartridges.
The court heard Mr Bangar’s family now live in fear.
Mr Bangar said: “I welcome them being jailed. For the first two months for my family, it was a very bad time. My wife wouldn’t be in the shop alone.
"Now slowly it is getting a bit better."