A West Islip High School student accused of bringing a gun and bullets to school on Monday pleaded not guilty to several weapons charges.

During the 17-year-old’s arraignment, the judge called his lack of judgment “astounding in today’s climate.”

The assistant district attorney said the student was showing his classmates a revolver that was tucked into his waistband on Monday. In addition, the student had 25 rounds of ammunition.

Police say the gun was legally registered, but not to the teen. They would not say who it was registered to. The defense lawyer said that the student’s father is a retired police officer and that he currently is an armed security guard for a school.

It is not clear why the teen brought the gun to school, but his attorney, Todd Greenberg, said the teen has never been arrested before.

Greenberg says his client made a “terrible decision” but there was never any intention to hurt anyone.

Suffolk County District Attorney Ray Tierney says, “I am thankful for the quick action of the West Islip school security staff and Suffolk County Police officers to prevent anyone from getting hurt here. We take these cases very seriously and our School Safety Unit vigorously investigates and prosecutes any threats to our children.”

Bail was set at $100,000 and the teen is due back in court on April 22.

If convicted as an adult, the teen faces 15 years in jail.