![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_5b8d47b8-2d8e-48c4-a1c3-88438159a9b7_1024x1024.jpg?v=1527196731)
Cooper is now drilling and tapping their new rifles for the larger 8-40 receiver screws... Date of this update notice May 24, 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.
The extended front ring brings the front ring 1/4" closer to the rear ring than the non-extended version. This extended option is typically used for rifles with a longer action and / or a scope with a shorter tube.