House Bill 25-1133, “Requirements for Sale of Firearms Ammunition,” was referred by the House Business Affairs and Labor Committee to the House for a vote following a lengthy debate by witnesses for both sides.

The bill passed only narrowly by a vote of 7-6, with Democratic Rep. Bob Marshall joining Republicans in opposing the legislation.

Amended to go into effect July 1, 2026, the bill would prohibit the retail sale of ammunition to a person who is younger than 21.

It would also require that ammunition sold in retail stores be “not accessible” without the assistance of an employee, practically requiring its storage in an enclosed display case or behind a counter.

Bill sponsors argued the later requirement would help prevent theft of ammunition from retail stores.

“It is far too easy for someone to simply walk out of the store with hundreds of rounds of ammunition,” said Democratic Rep. Monica Duran, a bill sponsor, during committee testimony. “This bill establishes basic security standards for ammunition sellers to prevent theft.”

Opponents of House Bill 25-1133, which included many small business owners, firearms instructors and even young members of the military, labeled it “unconstitutional.” They explained that ammunition theft is not a major problem and expressed concerns about the change in the age restrictions.

Erik Stone, Teller County commissioner and a National Rifle Association firearms instructor, detailed his concerns during public comment.

“I spoke with two different gun store owners just today on the way here to the Capitol, and I asked them bluntly, ‘Do we have an ammunition theft problem in Colorado?’ The answer was no, there is not,” he said.

Stone explained how many in his community have expressed concerns with the uptick in gun legislation in the state, with House Bill 25-1133 one of many introduced just this legislative session.

“They’re very concerned about the impacts to their ability to purchase, keep firearms and bear firearms, and now their access, or their children’s access, to ammunition,” he said.

Supporters of the bill included many Colorado students from the gun legislation advocacy group Students Demand Action, as well as family members of shooting victims.

“It was five bullets that took my sister Mary’s life in the lobby of Sandy Hook,” said Jane Dougherty. “It’s time for Colorado, with a sad track record of mass shootings, to meaningfully regulate ammunition.”

The bill would also change restrictions on shipping ammunition to the state. It would require a person shipping ammunition to give written notice to the ammunition deliverer that the package contains ammunition.

In addition, delivery drivers delivering ammunition would be required to verify that the person receiving the delivery is 21 or older and obtain written acknowledgment of receipt from the recipient. Failure to do so could result in a class 1 misdemeanor for the driver.

“This will help ensure ammunition stays out of the hands of people who should not have access,” said Democrat Rep. Lindsay Gilchrist, one of the bill’s sponsors. “Today, it is far too easy for our minors and others prohibited from owning firearms to evade minimal restrictions in place on these websites and stockpile ammunition.”

While the bill did pass, Republicans on the committee expressed great concern with the many different aspects of the legislation, but also that it was brought at all.

“What’s next when this doesn’t work?” asked Republican Rep. Chris Richardson. “And it won’t work unless we get to the root causes of violence in society. We are just going to keep looking at new laws and new restrictions that don’t do anything until the next one comes along and we find something else to restrict.”

Duran addressed concerns about the constitutionality of the legislation.

“There is a false narrative that the Second Amendment is absolute and unlimited,” she said at the conclusion of public comment. “This narrative is harmful, and it perpetrates a lack of collaboration between both parties when it comes to gun violence prevention.”