I would assume your groups to be under 2" at 100yd, not hard to do.What type of slug and what cal?Personally, any thing under 150yd,and standing reasonably still,I go for the base of the neck.Very little meat lose and no tracking.If both you and your rifle are up to the task, it' s all over in the blink of an eye, the most humane kill shot there is. Past 150yd,with good slugs,double lung,if you' ve got the " hitting power" , the animal won' t get up