The Leupold Steel Standard Bases are the most versatile of any mounting system. The rear ring is secured by windage adjustment screws, allowing the scope's internal adjustments to be reserved for precise sight-in. Additionally, shims can be used for gross elevation adjustment, reserving the scope's elevation adjustment for bullet drop compensation dial applications. SPECIFICATIONS - Fits: Winchester 70 RVR, right- and left-handed actions - Material: Steel - Type: Two-piece construction - Finish: Black Gloss.