Colorado’s New Semiautomatic Firearm Law Takes Effect Aug. 1
By Marissa Ventrelli | The Denver Gazette
A Colorado law passed in 2025 established new requirements for individuals planning to purchase semiautomatic weapons.
Here’s what residents should know before Senate Bill 003 goes into effect on Aug. 1.
From a ban to a training course
For decades, advocates have been pushing for a ban on semiautomatic weapons with detachable magazines, which they have described as “assault weapons,” though efforts escalated following the Columbine High School shooting in 1999.
After the 2012 movie theater shooting in Aurora, the Colorado legislature passed House Bill 1224, which prohibited the sale, transfer and possession of ammunition magazines capable of holding more than 15 rounds. However, some advocates wanted mor...


