Criterion stainless steel match grade button rifled barrels feature a 223 Wylde chamber and 1-8" twist for enhanced accuracy potential with both .223 and 5.56 NATO ammunition. Each Criterion barrel is individually hand-lapped to ensure smooth, consistent lands and grooves. Gas ports are optimized for barrel length and chambering to help ensure reliable cycling. Bull contoured stainless steel barrels incorporate an 11° target crown and barrel extensions featuring M4 feed ramps to aid in smooth, reliable feeding. Barrels now feature a dimple opposite the gas port, so screw-on gas blocks do not shift during firing.
Big Book Catalog, Issue:72, Page:025
SPECS: Length – 24 inches. Profile – Bull. Gas system –Rifle Length. Chamber - 223 Wylde. Finish – Stainless Steel. Construction – Gun Barrel Quality 416R Stainless Steel. Hand Lapped. Includes barrel extension with M4 feed ramps. Dimensions - .936” OD at the gas port. 1.9” length at gas block.