The group split and stole two cars, which they drove back to the South Auckland property.
The offenders then donned disguises - masks, hoodies and caps - and armed themselves with an array of weapons.
They took a pistol, a sawn-off shotgun, large screwdrivers, a drill and a crowbar, as well as plastic ties to restrain those at their targeted address ? The Whitehouse Tavern in Papakura.
At 10.45pm, after waiting in the pub's car park for two hours, they executed their plan.
All six offenders burst into the bar brandishing their weapons and screamed at patrons and staff to lie on the floor.
"You said they would have their heads blown off if they did not comply with your demands," Justice Ellis said.
After tying the victims up, they stole cell phones from patrons and cash from the bar's tills and one victim was seriously assaulted.
The offenders ran off, vaulting the fences of nearby properties before reaching one of the stolen vehicles in which they made their escape.
Meanwhile, the manager of the bar, who had slipped out of the backdoor while the robbery was in progress, called police who pursued the offenders.
A high-speed chase ensued and though they lost the following officers as they drove north, they crashed on O'Connell St in Manurewa.
They convinced a nearby resident to call a taxi but shortly afterwards they were tracked by police who stopped the cab and found a couple of the offenders, including the teenager, in the back.
The men had with them the loaded shotgun and some of the stolen goods.
Justice Ellis said the teenager was pressured into joining the offenders and did so because he had recently lost his job and wanted to support his pregnant partner.
