Criterion CORE Barrel + Gas Block Kit

The Criterion CORE Barrel Kit takes the guesswork out of AR-15 builds by bundling the acclaimed CORE Series barrel with a perfectly matched gas block system. This comprehensive kit addresses the two most common failure points in DIY builds: improper gas port sizing and misaligned gas blocks. By providing pre-matched, proven components, Criterion eliminates the trial-and-error process that frustrates many builders and can lead to reliability issues down the line.

Each kit includes the CORE Series barrel with its continuous taper profile, hand-lapped chrome-lined bore, and .223 Wylde chamber, paired with a gas block specifically sized and tested for that barrel configuration. The option for a pinned gas block provides additional security and simplifies compliance for pin-and-weld builds at 13.9" or 14.5" lengths. This integrated approach ensures the gas system functions reliably with both suppressed and unsuppressed fire from the first round.

For builders who want the satisfaction of assembling their own upper receiver but don't want to gamble on component compatibility, the Criterion barrel kit represents an ideal middle ground. The pre-dimpled gas journal ensures perfect alignment, while the included gas block eliminates sourcing headaches. Combined with Criterion's reputation for quality control and accuracy, this kit provides a solid foundation for any serious AR-15 build, whether destined for duty, competition, or recreational use.