Two shots hit the house, cracking the windows.
When spoken to by police, Shand said the victim had been harassing him and his dogs.
Defence lawyer Anna Brosnahan said there was an "ongoing dispute" between the neighbours and the victim was "well known to the police".
She said the dispute was "basically in relation to the state of the house next door and also the dogs going along the property".
"They're both trying to get on with their lives and get on with each other as best they can," she said.
Ms Willemsen said she knew the weapon was "only an airgun" but said it was "still a firearm".
Judge David Cameron remanded the matter to July 27 for sentencing.