Innovative, stripped receiver comes with many advanced features including an integral trigger guard and a screw-mounted bolt catch to eliminate the need for roll pins as well as a flared magwell for faster reloads and a reinforced buffer tube area for added strength. An upper tensioning screw is also provided to remove any play between the upper and lower receivers to give the gun a rock-solid feel. "Multi Cal" marked receiver is machined from a solid billet of 7075 T-6 aluminum and given a Type III, Class II hard anodized finish for maximum wear resistance and durability.