Doc,
I don't use just one test scope, but over the past decade have often relied on a 10x40 Leupold Mark 4 during initial testing of harder-kicking rifles chambered in longer-range rifles. Lately have also been using a 10x SWFA and a Nightforce 3-10x SHV for the same purpose.
When testing rifles chambered for moderate-range, harder-recoiling cartridges from the .375 H&H on up I usually use a 4x M8 Leupold.
