![Cooper Models 16, 22, 52, 54, 56, 92 Alloy Light Weight Ring Base Combination (xxx736 series) - store.TalleyScopeRings.com](http://store.talleyscoperings.com/cdn/shop/products/anschutz_alloy_99045100-73c3-4bb5-83f8-2c2afd864a0d_1024x1024.jpg?v=1469237335)
For rifles drilled and tapped for 6-48 screws... Cooper changed to the larger diameter 8-40 receiver screws in 2018...
Low .400 inch, Medium .500 inch, High .600 inch - as measured from the contact point at the receiver to the bottom of the ring cradle.