Eagle27, I do my best shooting with semi autos as I do not have to remove the firearm from the shoulder or break my grip.

Bolt guns, unless I am up close and shooting over/through open sights or using an Aimpoint I shoot one eye closed or squinting. Hand guns, semi autos, lever actions, shotguns I shoot with both eyes open. Mind you I have never used a semi auto or lever action with a magnification scope.