Every other Colorado firearms bill from the last two sessions gets argued about constantly—SB25-003, the ammunition rules, the magazine cap. SB25-205 is different. It received less attention, but the deadline for local agencies to begin offering its serial-number-check process passed on July 1, 2026. Here's what the statute actually does.
What the statute provides
SB25-205 is codified at C.R.S. 29-11.7-105. It allows—but does not require—a federally licensed firearms dealer (FFL) to request a serial number check before buying a used firearm from an individual. Think trade-ins and other situations in which a shop is purchasing a firearm rather than selling one.
Here's the mechanic: the dealer requests the check from local law enforcement — the police department if the shop is inside city limits, the sheriff's office if it's in unincorporated county territory. That agency has three days to run the check and respond, and the check has to say whether the firearm is reported stolen or lost, or is tied to an open criminal investigation. The agency can charge a fee to cover its actual cost of doing this — but if it doesn't respond within three days, it has to refund or waive that fee.
There's also a self-service option written into the law: if the federal government ever opens up its firearm tracing program (eTrace) for dealers to run these checks themselves, dealers can do that instead of going through local law enforcement. That provision isn't active yet — it's written to switch on "as soon as the technology and infrastructure" exists, and as far as we can tell that hasn't happened.
The part with teeth
If a dealer reasonably believes, knows or should know, or becomes aware that a firearm someone sold or tried to sell is stolen, lost, or connected to an open investigation, the dealer has 48 hours to report that information to the law-enforcement agency with jurisdiction over the dealer's business. Failure to report is handled through Colorado's dealer-permit enforcement statute, C.R.S. 18-12-401.5(7). That framework calls for a warning on a first offense and permits escalating consequences for later offenses, including fines beginning in 2027, suspension, or revocation of the state permit.
When it actually kicks in
This is the detail worth being precise about, because two different dates show up depending on where you look. Governor Polis signed SB25-205 on June 2, 2025, and as an ordinary bill without a safety clause, it technically became law 90 days after that year's legislative session ended — August 6, 2025. But the substance of the law is a separate compliance deadline written directly into the statute: "each sheriff's office or police department shall begin providing firearm serial number checks no later than July 1, 2026." That's the date that actually matters to dealers and agencies, and it's already passed as of this post.
Who this affects, and who it doesn't
This has nothing to do with SB25-003, the "specified semiautomatic firearm" list, eligibility cards, or anything we've spent most of this site covering. It doesn't touch new-gun purchases from a dealer's own inventory, and it doesn't create a state gun registry — the check is a point-in-time stolen/lost/investigation lookup, not a database of who owns what.
Where it does matter: if you're planning to trade in or sell a used firearm to a Colorado gun shop, the dealer may choose to request this check before completing its purchase. The statute gives the agency up to three days to respond, although actual dealer practices and response times may vary.
Why we're covering it now
Honestly, because it's exactly the kind of law that's easy to miss. It didn't generate protests, it isn't tangled up in federal litigation, and it was written at the request of dealers themselves rather than imposed against their objection — the Senate sponsor's office specifically credited firearm dealers in his district for raising the idea. But "boring and uncontroversial" isn't the same as "doesn't matter." If you sell guns for a living in Colorado, or you're about to trade one in, this is a real procedural change that's been quietly running since July 1.
As always, we are not lawyers—just Colorado citizens trying to understand the rules, statutes, and court decisions and share what we learn. The information on this website is for general informational purposes only and does not constitute legal advice, nor does it create an attorney/client relationship. The accuracy, completeness, or currency of the content is not warranted. Your use of content on this website is at your own risk. Consult an attorney about your specific circumstances.
