Ammunition and magazine laws in Colorado

(1) (a) A retail ammunition vendor shall not sell, offer for sale, or display for sale or transfer ammunition in a manner that allows the ammunition to be accessible to a purchaser or transferee without the assistance of the vendor or an employee of the vendor. Ammunition displayed in an enclosed display case or behind a counter or other customer access prevention device is not considered accessible for the purposes of this subsection (1)(a).
(b) (I) A retail ammunition vendor shall not sell ammunition to a person who is under twenty-one years of age. Prior to completing a sale of ammunition at an in-person transaction, the retail ammunition vendor, or an employee of the vendor, shall verify that the purchaser is at least twenty-one years of age by requiring the purchaser to produce a valid government-issued photo identification.
(II) (A) Notwithstanding the prohibition on selling ammunition to a person who is under twenty-one years of age described in subsection (1)(b)(I) of this section, a retail ammunition vendor is not prohibited from selling ammunition to a person eighteen years of age or older but under twenty-one years of age who was born on or before January 28, 2007.
(B) This subsection (1)(b)(II) is repealed, effective January 28, 2028.
(c) (I) Notwithstanding the prohibition on selling ammunition to a person who is under twenty-one years of age described in subsection (1)(b) of this section, the operator of a shooting range that provides opportunities for the public to engage in shooting sports or education may sell ammunition to a person who is eighteen years of age or older but under twenty-one years of age for use only at the shooting range. Prior to completing the sale of ammunition, the seller shall verify that the purchaser is at least eighteen years of age by requiring the purchaser to produce a valid government-issued photo identification.
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(e) This subsection (1) does not apply to the sale of rimfire ammunition.
(f) A retail ammunition vendor that violates this subsection (1) commits unlawful sale of ammunition. Unlawful sale of ammunition is a civil infraction; except that a second or subsequent offense is a class 1 misdemeanor.
(2) (a) A retail ammunition vendor delivering a package containing ammunition to a retail ammunition deliverer for purposes of transport shall use a delivery service that ensures that the person receiving the ammunition is twenty-one years of age or older through age verification.
(b) A retail ammunition deliverer must comply with 49 CFR 173.63 (b)(1)(i) related to the labeling and packaging for delivery of ammunition.
(3) (a) When delivering a package containing ammunition sold at retail, a retail ammunition deliverer shall:
(I) Verify that the person receiving the ammunition delivery is twenty-one years of age or older by requiring the person to present a valid government-issued photographic identification to the person making the delivery; and
(II) Obtain written acknowledgment of receipt of the ammunition delivery from the recipient of the delivery.
(b) (I) Notwithstanding the requirement to verify that the person receiving ammunition is twenty-one years of age or older described in subsection (3)(a)(I) of this section, a retail ammunition deliverer shall verify that the person receiving ammunition was born on or before January 28, 2007.
(II) This subsection (3)(b) is repealed, effective January 28, 2028.
(c) This section does not apply to a retail ammunition deliverer that does not know that the package contains ammunition because the sender failed to notify the deliverer that the package contains ammunition.
(4) This section does not apply to the sale or offer to sell ammunition at wholesale or the delivery of ammunition sold at wholesale.
(5) As used in this section, unless the context otherwise requires:
(a) "Retail ammunition deliverer" means an entity that delivers, by motor vehicle, ammunition sold at retail to the purchaser at a location in this state. "Retail ammunition deliverer" includes a retail ammunition vendor that delivers to a location other than the vendor's place of business ammunition sold by the vendor at retail to the purchaser.
(b) "Retail ammunition vendor" means a person who sells ammunition at retail. "Retail ammunition vendor" includes a vendor not located in Colorado when the vendor sells or offers to sell ammunition at retail for delivery to a purchaser located in Colorado.
Source: L. 2025: Entire section added, (HB 25-1133), ch. 89, p. 368, § 2, effective July 1, 2026.
18-12-118. Unlawful three-dimensional printing of a firearm or firearm component - penalties - definitions.

18-12-301. Definitions.
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(2) (a) "Large-capacity magazine" means:
(I) A fixed or detachable magazine, box, drum, feed strip, or similar device capable of accepting, or that is designed to be readily converted to accept, more than fifteen rounds of ammunition;
(II) A fixed, tubular shotgun magazine that holds more than twenty-eight inches of shotgun shells, including any extension device that is attached to the magazine and holds additional shotgun shells; or
(III) A nontubular, detachable magazine, box, drum, feed strip, or similar device that is capable of accepting more than eight shotgun shells when combined with a fixed magazine.
(b) "Large-capacity magazine" does not mean:
(I) A feeding device that has been permanently altered so that it cannot accommodate more than fifteen rounds of ammunition;
(II) An attached tubular device designed to accept, and capable of operating only with, .22 caliber rimfire ammunition; or
(III) A tubular magazine that is contained in a lever-action firearm.
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18-12-302. Large-capacity magazines prohibited - penalties - exceptions.
(1) (a) Except as otherwise provided in this section, a person who sells, transfers, or possesses a large-capacity magazine commits a class 1 misdemeanor.
(b) Repealed.
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(I) Owns the large-capacity magazine on July 1, 2013; and
(II) Maintains continuous possession of the large-capacity magazine.
(b) If a person who is alleged to have violated subsection (1) of this section asserts that he or she is permitted to legally possess a large-capacity magazine pursuant to paragraph (a) of this subsection (2), the prosecution has the burden of proof to refute the assertion.
(3) The offense described in subsection (1) of this section shall not apply to:

(x)(1) It shall be unlawful for a person to sell, deliver, or otherwise transfer to a person who the transferor knows or has reasonable cause to believe is a juvenile—
(A) a handgun; or
(B) ammunition that is suitable for use only in a handgun.
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(5) For purposes of this subsection, the term "juvenile" means a person who is less than 18 years of age.

Small Arms Ammunition: Ammunition is classified as a Division 1.1, 1.2, 1.3, or 1.4 explosive, depending on the degree of hazard. Ammunition that is regulated as a Class 1 explosive and designed to be fired from a pistol, revolver, rifle, or shotgun, as well as associated primers and blank cartridges (including those designed for tools) and propellant powder for use in any firearm, is prohibited from mailing.
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Shotgun Hulls, Empty Casings, Nonmetallic Shotgun Hulls, or Casings Without Primers: These articles are not classified as explosives or hazardous materials under 49 CFR and, therefore, are mailable, subject to the applicable mailing rules (refer to 224).