Brownells AR-15/M16 barrels, made for Brownells by Satern Barrels, feature 5R button rifling and are machined from 416R gun barrel steel for a superior shooting barrel. These 6.5 Grendel barrels feature a stainless steel finish. Barrels have 1-8 twist for excellent performance with a wide range of bullets. Available in 18” & 24” lengths. The 18” barrel features a mid-length gas system, while the 24” has a rifle length system. Muzzle is threaded 5/8"-24 and the gas shoulder accepts 0.750" gas block. Chamber is 6.5 Grendel II. Opposite side of gas port features a dimple for a gas block set screw. A 6.5 Grendel bolt is included with each barrel. Bolt is machined from 9310 steel with a bolt face depth of .136". Barrel extension is M4 feed ramp style.
AR-15, Issue:11, Page:018
Big Book Catalog, Issue:70, Page:016
Sinclair, Issue:5B, Page:248