However, instead they put salt in a plastic bag. Some of the group hid in bushes before the victim arrived.
Mowbray and another man arrived at the scene and Mowbray got in the victim's vehicle and offered the victim what he thought was methamphetamine. The men hiding in the bushes then emerged and threatened the victim with a firearm, demanding the "loot".
One of the men shot the victim in the thigh and hit him in the head with the gun. The victim got out to the car and tried to run away but, with the group's encouragement, the victim was shot again in the back. The victim then fell and rolled into a drain.
They then all left the victim and drove off. The victim survived but suffered serious injuries and needed surgery.
Justice Jagose said during sentencing Mowbray was 25 at the time, had support from family and had acknowledged his drug and alcohol issues.
It said he had suffered from anxiety and depression and he had shown signs of remorse.
He was already having counselling in prison and had been diagnosed with post-traumatic stress disorder from a separate event.
Justice Jagose said while Mowbray didn't initiate the plan, he joined in and played his part in planning it.
Justice Jagose reduced the previous term of imprisonment from six years and one month to five years and five months.