A federal judge has left Hawaii's gun age limit in place, a win for the state and a loss for 18- to 20-year-olds who wanted to buy guns.

• Hawaii's minimum age to buy or own a firearm stays at 21.
• A US District Court judge threw out a challenge from people who said the rule tramples the Second Amendment rights of adults under 21.
• The court leaned on history, finding a long American tradition of keeping guns out of the hands of people under 21.
• Adults aged 18 to 20 in Hawaii remain barred from buying or possessing firearms.

Outlook: The plaintiffs are likely to appeal, keeping the age limit in play in higher courts.