Criterion Barrels 18in AR-15 Hybrid Rifle Gas System Barrel Chrome-lined Parkerized. Criterion Barrels uses button rifling and manufactures these AR15 Barrels from gun barrel quality steel. Criterion Barrels AR-10 Hybrid Rifle Length Gas System Barrels provide high accuracy with lighter weight. For high quality barrels at affordable prices choose Criterion Barrels AR-15 Mid-Weight Hybrid Match Grade Barrels. Specifications for Criterion Barrels AR-15 Hybrid Rifle Gas System Barrel: Manufacturer: Criterion Barrels Color: Black Finish: Parkerized Fabric/Material: Steel Caliber: .223 Wylde Barrel Profile: Hybrid Gas System Length: Rifle Length Gas Block Journal Size-Diameter: .750 in Threads per Inch: 1/2x28 Barrel Twist Rate: 1-8 Gun Make: AR Platform Gun Model: AR-15 Additional Features: M4 Barrel Extension Condition: New Country of Origin: USA Features of Criterion Barrels AR-15 Hybrid Rifle Gas System Barrel Chrome-lined internally for superior barrel life and corrosion resistance. Their chrome-lining process is the most refined in the industry and will not degrade accuracy. .223 Wylde chamber that is designed to safely and effectively fire both .223 Remington and 5.56 NATO ammunition Honed and hand-lapped rifling for bore uniformity and a pristine internal finish - aids in barrel cleaning and paramount for accuracy Finely polished chambers for reliable extraction and feeding Carbine gas system compatible with AR15 gas tube system Gas hole tuned for proper function with and without suppressor 0.750" Gas Block dimpled for ease of installation and solid lock-up 1/2x28 TPI muzzle threads compatible with a wide range of muzzle devices and suppressors Precision-machined barrel extension with M4 feed ramp Package Contents: Criterion Barrels AR-15 Hybrid Rifle Gas System Barrel What firearm models does the manufacturer say Criterion Barrels AR-15 Hybrid Rifle Gas System Barrel is compatible with? The manufacturer suggests that Criterion Barrels AR-15 Hybrid Rifle Gas System Barrel is compatible with AR-15Criterion Barrels 15180-HY12: 18in AR-15 Hybrid Rifle Gas System Barrel Chrome-lined Parkerized