Colorado Ammunition Laws: Age, Excise Tax, and Magazine Limit

Colorado ammunition laws now set 21 as the general minimum age to buy ammunition at retail, add a 6.5 percent state excise tax at the register, cap magazine capacity at 15 rounds, and require retailers to keep ammunition behind the counter. Federal law layers on top, barring people with felony convictions and qualifying domestic violence histories from possessing ammunition at all.

Who Can Buy Ammunition in Colorado

Federal law sets the floor. Licensed dealers cannot sell rifle or shotgun ammunition to anyone under 18, and cannot sell handgun ammunition to anyone under 21.¹

Colorado goes further. HB25-1133 prohibits the retail sale of any ammunition to anyone under 21, with the law taking effect in 2026.² Several exceptions let 18-to-20-year-olds buy in person:

Purchases at a shooting range for immediate use there.
Active-duty service members and veterans.
Buyers holding a hunter education certificate.
People protected by a court-issued protection order.
Anyone born on or before January 28, 2007.
Rimfire cartridges such as .22 LR, regardless of buyer age above 18.
Peace officers purchasing while on duty.

A retailer who sells in violation of these rules faces a civil infraction for a first offense. A second or later violation is a class 1 misdemeanor, punishable by up to 364 days in jail and a fine up to $1,000.²

How Ammunition Must Be Sold and Shipped

At brick-and-mortar stores, ammunition must be kept so customers can only access it with an employee’s help.² In practice, ammunition goes behind a counter or into a locked display rather than on open shelves.

Online orders carry extra requirements. The retailer must use a delivery service that verifies the recipient is at least 21, and the recipient must sign a written acknowledgment at delivery. Packages cannot be labeled on the outside as containing ammunition. These shipping rules also cover reloading components, because the law defines ammunition broadly to include cartridge cases, primers, propellant powder, and projectiles. Handloaders ordering supplies online are covered by the same delivery rules.

The 6.5 Percent Ammunition Excise Tax

Colorado voters approved Proposition KK in November 2024, creating a 6.5 percent excise tax on retail sales of firearms, firearm precursor parts, and ammunition. Collection began April 1, 2025.³ The tax is added at the point of sale, on top of regular sales tax.

Three categories of buyers are exempt: peace officers, law enforcement agencies, and active-duty members of the U.S. Armed Forces. Exempt buyers document the purchase using state affidavit form DR 7612.⁴

Vendors must register with the Colorado Department of Revenue before selling, with a separate registration for each location, and renew every two years. Monthly excise returns are required. A small-seller exception applies: a retailer whose total firearm and ammunition sales were $20,000 or less in the previous calendar year does not owe the tax unless current-year sales exceed that threshold.³

Who Is Prohibited From Possessing Ammunition

Under 18 U.S.C. § 922(g), anyone convicted of a crime punishable by more than one year in prison is barred from possessing any firearm or ammunition, regardless of where the conviction occurred. The same statute bans ammunition possession by people subject to qualifying domestic violence protection orders and by anyone convicted of a misdemeanor crime of domestic violence.¹

Colorado adds its own prohibition. Under C.R.S. § 18-12-108, a person convicted of a felony or an attempt or conspiracy to commit a felony cannot possess firearms and other weapons covered by the state’s weapons statutes. A violation is a class 5 felony carrying one to three years in prison.⁵ Probation is off the table if the person used or threatened to use a firearm during another crime.

Protection Orders and Surrender Deadlines

When a Colorado court issues a civil protection order involving domestic violence that included the threat, use, or attempted use of physical force, the respondent must stop possessing any ammunition for as long as the order lasts. The deadline is 24 hours if served in court, 48 hours if served elsewhere, excluding weekends and holidays.⁶

Compliance has three paths: sell or transfer the ammunition to a federally licensed dealer, arrange storage with law enforcement or a sheriff-contracted facility, or sell to a private party who can legally possess it. The same surrender requirement applies to anyone subject to an Extreme Risk Protection Order under C.R.S. Article 13-14.5.

The 15-Round Magazine Limit

Since July 1, 2013, Colorado has banned the sale, transfer, or possession of large-capacity magazines. Under C.R.S. § 18-12-302, that means any fixed or detachable magazine, box, drum, or feed strip holding more than 15 rounds. For shotguns, the definition also covers fixed tubular magazines longer than 28 inches and detachable shotgun magazines holding more than eight shells when combined with a fixed magazine.⁷

A few things fall outside the ban. A feeding device permanently altered so it cannot hold more than 15 rounds does not count. Tubular magazines attached to lever-action rifles are exempt. Attached tubular devices designed exclusively for .22 caliber rimfire ammunition are also exempt.⁷

Anyone who owned a large-capacity magazine before July 1, 2013, may keep it, but only with continuous possession.⁸ The grandfathering is personal and does not transfer. Giving, selling, lending, or passing a pre-ban magazine to someone else leaves the recipient with no legal right to possess it. Inheriting a pre-ban magazine does not carry the exemption forward. A violation is a class 2 misdemeanor, punishable by up to 120 days in jail, a fine up to $750, or both.

Prohibited Ammunition Types

Colorado has no separate state law banning specific ammunition types such as armor-piercing, incendiary, or explosive rounds. The state’s dangerous-weapons statute, C.R.S. § 18-12-102, does not address ammunition composition.⁹

Federal law covers that gap. Under 18 U.S.C. § 922, restrictions apply to the manufacture, importation, and sale of armor-piercing ammunition by licensed dealers.¹ Armor-piercing handgun ammunition is not sold legally at Colorado retailers as a practical matter. Standard commercial rifle and handgun ammunition from a licensed Colorado dealer is almost certainly legal under both state and federal law.

Local Ammunition Ordinances

Colorado repealed state preemption of local firearms and ammunition laws in 2021. Under SB21-256, any city or county can pass its own rules on the sale, purchase, transfer, or possession of ammunition, so long as the local law is not less restrictive than state law.¹⁰ A local ordinance can only impose criminal penalties on someone who knew or reasonably should have known the conduct was prohibited.

Denver is the clearest example. The city’s definition of certain “assault weapons” turns partly on ammunition capacity, including rifles holding more than 15 rounds and semiautomatic shotguns with a folding stock or magazine capacity above six rounds. If you travel between Colorado communities, check the local rules. They vary.

Ammunition-Only Purchases and the Waiting Period

Colorado’s three-day waiting period from HB23-1219 applies to the delivery of firearms, not to standalone ammunition purchases.¹¹ Buying ammunition without a firearm triggers no state waiting period and no state background check for the ammunition itself. The wait only affects your ammunition when you buy a firearm and ammunition together, because the dealer holds the whole transaction until the firearm is released.

1
Office of the Law Revision Counsel. 18 USC 922 – Unlawful Acts
2
Colorado General Assembly. HB25-1133 Requirements for Sale of Firearms Ammunition
3
Colorado General Assembly. HB24-1349 Firearms and Ammunition Excise Tax
4
Colorado Department of Revenue – Taxation. Firearms and Ammunition Tax
5
Justia Law. Colorado Code 18-12-108 – Possession of Weapons by Previous Offenders
6
Justia Law. Colorado Code 13-14-105.5 – Civil Protection Orders – Prohibition on Possessing or Purchasing a Firearm
7
Justia Law. Colorado Code 18-12-301 – Definitions
8
Justia Law. Colorado Code 18-12-302 – Large-Capacity Magazines Prohibited – Penalties – Exceptions
9
Justia Law. Colorado Code 18-12-102 – Possessing a Dangerous or Illegal Weapon – Affirmative Defense – Definition
10
Colorado General Assembly. SB21-256 Local Regulation of Firearms
11
Colorado General Assembly. HB23-1219 Waiting Period to Deliver a Firearm