Terry
Is your double scoped?
I tested my 9,3x74R Chapuis [with scope] at 200 and 300 yards and was suprised how well it shot that far away. I have killed a coyote at 271 yards, firing kneeling, and a kudu at a little over 300 yards in Zim using a bush for support.
I have shot a caribou at 150 yards [iron sights] with my 450/400,firing off hand.
Test your double at 200 and 300 yards.