One of the texts referred to an earlier Facebook posting about an argument with neighbours over the manner of Mr Brew's driving.
One of the text messages Dickson sent to Ms Freemantle said: "I read face book u nothing but a **** u so much as get near hurting one of those kids driving like a **** an I finish it."
At 1am on September 8, Dickson said, he decided to go out shooting possums at Norlings Rd, close to Ms Freemantle's home.
Ms Freemantle said that about 1am she and Mr Brew heard a car travelling at speed over gravel on Norlings Rd.
They went outside and heard two gunshots before seeing Dickson driving slowly back up the road.
Both Ms Freemantle and Mr Brew said they saw Dickson holding a gun in the car.
The complainants also alleged in court that Dickson pointed the firearm at them but this was not contained in their original statement to police.
Mr Brew also said that he heard another two or three shots a few minutes later.
Under questioning from prosecutor Sergeant Garry Wilson, Dickson said he had been shooting possums and magpies.
Two shotgun shells were later found by police 170 metres and 237m away from the residence.
Judge Stephen Harrop said he rejected Dickson's evidence that there was no connection between the shots and the texts. "It is unbelievable that you sent abusive texts and you turned up at her place with a shotgun. Frankly, that beggars belief."
Judge Harrop said there was no evidence that Ms Freemantle and Mr Brew were frightened by the discharge of the gun and he dismissed the firearms charge on that basis.
"In addition, even if I had thought that it was the case, I would not be of the view the firearm was discharged near to the premises."
Judge Harrop said it was not up to Dickson to act as a "vigilante" despite his personal feelings on Mr Brew's alleged driving.
He convicted Dickson on the offensive texts charge.
"For any woman to receive a text message like that, you must have known you were going to cause grave offence to her." He fined Dickson $350 and directed that he pay court costs of $152.89.