The Criterion Barrels Hybrid contour is a mid-weight barrel that offers a perfect balance between weight and intelligently distributed barrel material for excellent heat absorption and consistent harmonics. This barrel can be easily carried in the field all day but will also provide exceptional performance even under extreme use and high rates of fire.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. FeaturesHoned 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 suppressorGas Block dimpled for ease of installation and solid lock-up