Fluting aids in removing weight while maintaining rigidity. Criterion Barrels fluted barrels feature eight flutes around the circumference of the barrel to both the front and rear of the gas block journal. Each flute is polished to remove any sharp edges while maintaining a crisp appearance.Headspace (the bolt to barrel fitment), must be checked for optimal performance and reliability. Proper headspace produces consistent chamber pressures and seating depths which results in increased accuracy and reliability, while reducing wear and tear on internal parts and components. FeaturesPolished stainless steel finishHoned and hand-lapped rifling for bore uniformity and a pristine internal finish - aids in barrel cleaning and paramount for accuracyFinely polished chambers for reliable extraction and feedingGas hole tuned for proper function with and without suppressor750" Gas Block, dimpled for ease of installation and solid lock-up1/2x28 TPI muzzle threads compatible with a wide range of ...