MDT's Scope Base Pic-atinny Rails are designed to make the mounting of your optics easier. They are machined from 6061-T6 aluminum, then hard-anodized black for a durable finish. The underside of the rails are profiled to allow the rail to be mounted flush on the receiver and to match the geometry of the ejection port. These rails are designed with a 20 MOA incline providing additional elevation adjustment from your scope*. A recoil lug has been integrated in the underside rail profile on models where the action's design allows for this feature.