SLR Rifleworks Premium Bolt Carrier Group Black Nitride - 556

SLR Rifleworks Premium Bolt Carrier Group Black Nitride - 556Features Lugs are machined with the proper radius as per true mil-spec tolerances. Independent HP white proof testing exceeded 90,000 PSI without failure. Outer diameter machined to all critical surfaces within +/.0005 inches. Rounded cam pin rides in a fully chamfered cam path. Gas key with rounded leading edges ensures positive functioning in all makes and grades of uppers and buffer tube combinations. Properly staked and torqued grade 8 hex screws as per the true mil-spec. Carrier body OD and ID are hard turned after heat treatment to +/.0005 inchesSpecifications Carrier Assembly: The enhanced bolt carrier is designed to reduce carrier tilt/cant during recoil and increase reliability by strategically relocating key bearing surfaces. Material: Case-hardened 8620 steel (complete care is taken during the heat treat process, so as not to harm the metal) Finish: Black Nitride Gas Key: 4130 Steel, attached with Grade 8 hardware, torqued and properly staked into a milled "valley" around a fully encased ejection port area, for added strength and rigidity. Cam Pin: Hardened 4340 cam pin. Firing Pin: Mil Spec firing pin made of 8740 steel, center-less ground, and Hard Chrome coated. Bolt Assembly: The Bolt is a "true" Mil Spec dimension, and external surfaces are CNC ground after heat treat for a precision fit. These bolts are held to the highest possible tolerance. The "trumpet" area behind the gas rings, where carbon normally collects, is precision CNC-ground after heat treatment to ensure as smooth an area as possible, easing cleanup and improving longevity. Material: 9310 Case Hardened Steel Finish: All Bolt components Shot Peened & Nitride Finish Extractor: 4340 Steel, Nitride Finish Magnetic Particle Inspected (MPI) and High Pressure Tested (HPT) Mil Spec Extractor Spring & O-Ring