By pinning your gas block in addition to using set screws, you can be sure that your gas block will stay secure throughout your shooting session. We've simplified the pinning process by pre-notching the gas block journal on some of our most popular barrel models and pre-drilling corresponding holes in the included low-profile gas block. Each pinned gas block barrel includes both the pin and gas block, with the blocks hand-tightened for shipping. The gunner profile combines the best features of the Gov't and Pencil profiles, merging the strength of the Gov't profile with the lightweight, maneuverable qualities of the Pencil. This balance shifts the rifle's weight closer to the shooter's body, reducing fatigue for all-day shooting, training or hunting. Faxon Firearms barrels are crafted in-house in Cincinnati, Ohio and undergo rigorous stress relief, air Gauge testing and 11 degree target crowning for exceptional accuracy. Constructed from certified 4150 mil-spec steel or 416-R stainless, each barrel is tested at every stage of production before being finished with a nitride coating and thoroughly 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