Towards the rear of the action.
The added height in the rear of the base adds 20 MOA. In effect, your scope is actually lower in the front than the rear, providing adjustment over a higher yardage/meter range.
Most scopes only have 40 MOA of usable adjustment. They may have more, but some of the internal scope adjustment is used to zero the scope on your action. So, you use up 20 MOA of adjustment to zero the scope, leaving only 20 MOA to dial up to varying distances.
With the 20 MOA base, your scope is now at the beginning or bottom of the 40 MOA of usable adjustment, therefore, you have 40 MOA of vertical adjustment in your scope.
Bookmarks