All depends on the scope, most north american scopes move the bullet impact on the target, some european scopes move the cross hairs to the bullet impact. I own both, and one of them requires a lot more ammo to sight in then the others, I blame this on a design flaw
european are using 1cm at 100m, 1.5cm at 100m or 1cm at 50 meters european: have a great sense of humour .... you need a meter to makes some changes also.