A Grand Rapids teen who fired a rifle during a party, striking a young mother in the head, was sentenced Thursday to between eight and 15 years in prison for what the judge called “extremely gross negligence and carelessness.’’

The March 20 shooting killed 18-year-old Kiara Carter, who was attending a party with about a dozen others at an apartment on Kalamazoo Avenue south of Franklin Street SE.

The gunman, 16-year-old Cleo Malik Nelson, pleaded guilty to manslaughter, a 15-year felony. In exchange for his plea, a charge of open murder was dismissed.

“You had an assault rifle with a fully-loaded magazine,’’ Kent County Circuit Court Judge Mark Trusock said. “It’s my understanding she asked you to unload it. You took the magazine out and then you pointed the gun at her and shot her in the head. There was one left in the chamber.’’

Trusock noted that just a few weeks earlier, Nelson had a loaded handgun that discharged “as a result of you throwing it on the floor.’’

“This is not an accident by any means,’’ the judge said of the fatal shooting. “An accident is when you trip and fall. This was extremely gross negligence and carelessness.’’

Nelson's guilty plea came in July, but a separate hearing was held last month to determine if he should be sentenced as an adult or as a juvenile. Trusock opted to sentence Nelson as an adult, noting the teen's criminal record and failure to make positive changes.

“Young man, I hope everyday you’re sitting in prison you think about the life that you took in this manner and the pain that you caused this family,’’ Trusock said.

Nelson has faced numerous criminal charges dating back to 2014, including larceny, aggravated assault and assault with intent to do great bodily harm less than murder.

“You are another fine example of the failure of the juvenile system,’’ the judge said. “You’ve been through every program that they’ve had.’’

Members of the victim’s family attended Thursday’s sentencing, but did not comment. They held a framed image of Carter in the back Trusock’s 11th floor courtroom.

Defense attorney Brett A. Stevenson said Nelson is “very remorseful.’’

“This is a crime of negligence,’’ Stevenson said. “Mr. Nelson had nothing against the victim; there was no arguing between him and the victim. He picked up a gun which he should have known better not to do. Unfortunately, we cannot turn back the clock and go back in time.’’