A federal judge on Thursday upheld a 2023 Colorado law generally increasing the age to purchase firearms, after the challengers acknowledged a recent federal appeals court decision dictated the outcome.

Senate Bill 169 created a misdemeanor offense for those who sell guns to people younger than 21. Similarly, it became a misdemeanor for someone under 21 to purchase a gun. The law created exceptions for police officers, those in the military or gifts from family members.

U.S. District Court Chief Judge Philip A. Brimmer initially granted a preliminary injunction after concluding the challengers demonstrated they would likely succeed in their claim that the Second Amendment protected the right of 18-to-20-year-olds to buy guns. However, a three-judge panel of the U.S. Court of Appeals for the 10th Circuit disagreed in November.

An age-based condition on the commercial sale of guns, wrote Judge Richard E.N. Federico, does not run afoul of the right to “keep and bear” arms under U.S. Supreme Court precedent.

Colorado’s law “neither prohibits anyone from possessing a gun nor prohibits certain non-purchase gun transfers of ownership,” Federico explained in the Nov. 5 opinion. “In fact, the federal government, almost all 50 states, and the District of Columbia have each implemented a minimum age requirement for some or all firearm purchases.”

After the 10th Circuit overturned Brimmer’s injunction, the parties both moved to end the case in their favor. However, the plaintiffs, consisting of the gun advocacy group Rocky Mountain Gun Owners and two Coloradans under 21, conceded the 10th Circuit had doomed their challenge.

“Nevertheless, they seek to preserve their arguments for further review,” wrote attorney Barry K. Arrington, referring to potential consideration of the case by the Supreme Court or by the entire 10th Circuit bench. He added that at least one other federal appeals court reached a different conclusion than the 10th Circuit when analyzing a similar law.

“The Court agrees that the Tenth Circuit has resolved plaintiffs’ claim,” Brimmer wrote in a June 5 order. “Therefore, as a matter of law, plaintiffs cannot establish a violation of a right secured by the Constitution or that they have suffered an irreparable injury from such a violation.”

The case is Rocky Mountain Gun Owners et al. v. Polis.