A Taranaki man snapped after 18 months of torment from boyracers and shot at one of their cars, prosecutors told a court yesterday.

Stan Milne, 53, went on trial int New Plymouth District Court charged with recklessly endangering the safety of the car's driver Scott Wilson, then aged 17, and his passenger, Sandy Perrett, after an incident in May, 2008, the Taranaki Daily News reported.

Crown prosecutor James Gurnick said Milne fired a .22 rifle into a car doing "doughnuts" and "snakies" in front of his family home near Egmont Village, outside New Plymouth.

Mr Wilson, now aged 20, admitted he had gone to the street to do doughnuts and slides about 3am after a drinking session and had heard a couple of loud bangs as he performed a doughnut at the end of the road near Milne's house.

He told the court he thought it was large rocks hitting the tyre well, but the next day found a hole in the left back brake light and used tweezers to recover a .22 bullet.

The following day he found a ragged hole in the number plate and discovered a second .22 bullet in the boot, he said.

However, Milne's defence counsel Susan Hughes, QC, said the teenager had been the one who fired the .22 shots into his own car, keeping the bullets inside his car so he could brag to his mates.

Milne's wife, Heather Milne, also took the stand yesterday and told the jury the family's peaceful life had been badly affected by boyracers, and that their horses often got spooked by the loud noise.

She said Milne fired two or three shots from a slug gun that night, but that the rest of their firearms were kept in a gun safe in the garage.

Asked why her husband had snapped and fired the slug gun, Mrs Milne said sheer frustration.

"Frustration at being hassled by this particular person for so long."

The day before the incident with Mr Wilson, Milne had tracked down the owner of a Honda motorbike and told the man's daughter he would put a bullet through his head if he scared his horses again.

He yesterday admitted a charge of threatening grievous bodily harm to the man.