Great for long-range shooting, the Leupold BackCountry Cross-Slot 1-Piece Base with 20 MOA for Winchester 70 Short Action Rifles is designed with a 20-MOA slope. The matte base is made of 7075-T6 aircraft-grade aluminum to last in the field and fits Picatinny and Weaver rings. Leupold BackCountry Cross-Slot 1-Piece Base with 20 MOA for Winchester 70 Short Action Rifles Black - Scope Rngs And Rifle Accessories