Depends on where you hit them Alan. A deer shot in the spine will drop in it's tracks. Sometimes the shock from the slug will be enough to drop some deer where they stand, even if they're not hit in the spine. The safest place to shoot is either right behind the shoulder about two thirds of the way down from the back, or right at the shoulder the same distance down. I've never seen a deer, no matter the size, run very far when you pass a slug through the front shoulder. If you're not familiar with the vitals of a deer, go to any sporting goods store and look at a 3-D target of a buck or doe. Hope that helps.