Federal Judge Upholds Colorado Law Barring Gun Sales to Adults Under 21
On June 6th, 2025, a federal judge ruled in favor of a controversial Colorado law that bans the sale of all firearms to adults under the age of 21. This ruling marks the latest development in the legal battle over SB23-169—a law critics say unjustly strips legal adults of their constitutional rights.
Signed into law by Governor Jared Polis in April 2023, SB23-169 prohibits licensed dealers and private sellers from transferring any firearm to someone aged 18–20. The law includes narrow exceptions for active-duty military personnel and certain law enforcement officers. It officially took effect in August 2023, but had been temporarily paused due to a legal challenge brought by Rocky Mountain Gun Owners (RMGO).
A Fight Years in the Making
When the law was signed, RMGO immediately filed a lawsuit, asserting the age restriction violated the Second Amendment. A U.S. District Court initially agreed, issuing a preliminary injunction halting the law from taking effect. But that ruling was overturned by the Tenth Circuit Court of Appeals in late 2024, allowing enforcement to proceed while the underlying case continued.
Now, Judge Philip Brimmer—who originally granted the injunction—has reversed course. In his latest ruling, Brimmer sided with the state, concluding that the plaintiffs failed to demonstrate that the age-based restriction on firearm sales violated their constitutional rights. He cited the Tenth Circuit’s finding that such restrictions are “presumptively lawful” under historical tradition and consistent with longstanding limitations on commercial firearm transactions.
Judge Brimmer – Image Courtesy of USCourts.gov
This of course, is all unrelated to the new law passed this year that prohibits the purchase of ammunition by anyone under the age of 21 as well.
Implications for Young Adults
This ruling leaves a class of law-abiding legal adults without access to a core constitutional right. In response to the decision, RMGO called it “disgraceful” and vowed to consider further appeals. For now, however, the law remains in full effect, cementing Colorado as one of several states to raise the minimum firearm purchase age to 21, going beyond federal law that already restricts handgun purchases by age.
This isn’t the first time lawmakers have used age as a regulatory lever to curb access to firearms, and Colorado’s move is part of a broader national trend. But the questions remain: When are you considered responsible enough to vote, marry, or serve in the military, but not trusted to exercise your right to self-defense?
We’ve previously explored this issue in-depth. For more background and national context, read our feature: “Legal Adults, Limited Rights: The Second Amendment Fight for 18–20-Year-Olds”.
Looking Ahead
The outcome of this case may eventually find its way to the U.S. Supreme Court, especially as conflicting rulings on similar laws emerge in other circuits. Until then, young adults in Colorado remain second-class citizens when it comes to their right to keep and bear arms.