A new bill introduced in Colorado is sparking serious Second Amendment debate. Colorado Senate Bill 26-43 would regulate the sale and transfer of firearm barrels as if they were complete firearms—potentially making it a crime for private citizens to sell a simple metal tube without going through a federally licensed dealer (FFL).

Under the proposed law, firearm barrels could only be transferred in person through an FFL. Private sales would be prohibited, and even possessing a barrel “with intent to sell” could result in misdemeanor charges, fines, and up to 30 days in jail. The bill also requires detailed recordkeeping, with dealers maintaining buyer information for five years and submitting tracking forms to the Colorado Bureau of Investigation.

The definition of a “firearm barrel” in the bill is broad. It includes not only finished barrels but also partially completed components such as forgings, castings, and machine bodies that could be made into barrels. Critics argue this language mirrors previous regulatory efforts targeting unfinished receivers and so-called “80% lowers.”

Opponents point directly to the U.S. Supreme Court’s 2022 decision in New York State Rifle & Pistol Association v. Bruen, which established that firearm regulations must align with the nation’s historical tradition of gun laws. Under the Bruen framework, if conduct is covered by the plain text of the Second Amendment, the government must demonstrate a historical analogue from the founding era.

Gun rights advocates argue there is no historical precedent from 1791 for regulating standalone firearm barrels or criminalizing private transfers of gun components. Early American gunsmithing was decentralized, and private trade of parts was common practice.

Supporters of the bill, however, frame it as a public safety measure aimed at closing perceived loopholes in firearm commerce.

If passed, Senate Bill 26-43 could become a major legal test case under Bruen. Legal challenges would likely focus on whether regulating non-serialized components like barrels constitutes an unconstitutional burden on the right to keep and bear arms.

As states continue to explore new regulatory approaches, Colorado’s proposal may signal a broader trend of targeting firearm components rather than complete firearms—setting up another potential showdown in federal court.