Criterion Barrels: 12.5" Barreled Upper Receiver
This video details a custom 12.5-inch AR-15 upper receiver build by Criterion Barrels, focusing on optimizing timing and reliability. Key improvements include truing the receiver face, upgrading to a full-mass BCG, and recommending an H3 buffer to manage dwell time. Accuracy testing demonstrated sub-MOA potential, with a best group of 0.75 inches.









