Crossbow's Effective Range
Though a crossbow has similar characteristics to firearms, with the stock, scope and trigger, it is important for hunters to remember that crossbows have a similar effective range as bows and arrows. The maximum recommended range for hunting with a crossbow is 40 yards, provided the animal is not aware of your presence and is not moving quickly.
Be sure you practice at the yardage you expect to find game, and ensure you are able to properly estimate distance. You can use a range finder which can be mounted onto your crossbow, and will always provide an accurate range to your target.