A 65-year-old north Florida man who had been sentenced to 20 years in prison for firing shots into the ground has been granted a new trial.

A Clay County judge ruled jury instructions were flawed in Ronald Thompson's 2010 trial, and he was set free Wednesday night.

The Gainesville Sun reports that Thompson was talking to a woman on the porch of her Keystone Heights home in September 2009 when her teenage grandson arrived with three friends. The woman and her grandson got into a heated argument, and Thompson, who had a concealed weapons permit, went to his truck, got his handgun and fired two shots into the ground.

Thompson was charged with four counts of aggravated assault. He rejected a plea deal for three years and was convicted at trial. State sentencing requirements meant a mandatory 20-year sentence.