For those looking to maximize the accuracy of their AR-15 rifles, the Criterion Bull Contour provides the competitive advantage. A favorite amongst competition and long-range shooters, Bull Contour AR-15 barrels are optimized to push .223 Remington and 5.56 NATO cartridges to their limits. FeaturesPolished stainless steel finish.223 Wylde chamber that is designed to safely and effectively fire both .223 Remington and 5.56 NATO ammunitionHoned 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 feedingRifle gas system compatible with AR15 gas tube systemGas hole tuned for proper function with and without suppressor0.936" Gas Block, dimpled for ease of installation and solid lock-up11-degree target to reduce potential muzzle damagePrecision-machined barrel extension with M4 feed ramps