She said Mr Bushell's father had spoken about how the control of his life had been taken away from him and he had been robbed of the ability to go hunting and fishing with his son.
Justice Thomas' starting point for the length of the prison term was seven and a-half years. She then reduced that to five years and eight months after taking account of him being a first offender, his age of 19 when he shot Mr Bushell, his offer to plead guilty to manslaughter a week before the trial began, and his remorse.
She did not accept Crown Prosecutor Greg Hollister-Jones' argument that the shooting was a vigilante action. However she said it was difficult to conceive of a more dangerous action than to point a firearm at someone at close range and pull the trigger.
"He knew what damage a shotgun could do."
Last month, Flavell was found guilty of manslaughter.
The sentencing comes just after the anniversay of Mr Bushell's death.