Pinning your gas block alongside using set screws gives you extra peace of mind, ensuring your gas block stays securely in place while firing. We've taken the hassle out of pinning by pre-notching the gas block journal on some of our most popular barrels and drilling corresponding holes in the included low-profile gas block. Each pinned gas block barrel comes with the necessary pin and gas block, with the blocks hand-tightened to the barrel for shipping. The gunner profile combines the best features of the Gov't and Pencil profiles, offering both the durability of the Gov't and the lightweight maneuverability of the Pencil. This design helps balance the rifle towards the shooter's body, reducing fatigue for extended shooting sessions. Faxon Firearms barrels are built with superior quality in-house in Cincinnati, Ohio. Fully stress-relieved, air Gauge tested and 11 degree target crowned, they're made from certified 4150 mil-spec steel or 416-R stainless for maximum performance. After a series of stringent tests, each barrel is finished with a nitride coating and meticulously inspected for headspace using precision PTG Gauges. 11 degree target crown Twist rate - 1:8 Gas block diameter - 0.625 inches Gas block journal length - 1.9 M4 barrel extensions Mid-length, button-rifled, gunner barrel Magnetic particle inspection (MPI) for optimal performance to ensure optimal performance, it is essential to conduct magnetic particle inspection (MPI) with precision and adherence to established protocols This non-destructive testing method is employed to detect surface and near surface discontinuities in ferromagnetic materials By applying a magnetic field to the test object and introducing magnetic particles, any disruptions in the magnetic field caused by defects become visible, allowing for accurate identification and assessment Proper execution of MPI requires a thorough understanding of the equipment, materials and techniques involved, as well as strict compliance with safety standards and guidelines