There's been a lot of discussion on here as to how many pellets are enough, but even if you hit him with the whole load I agree that 40 yards is max, 30 even better. My opinion is that slugs are a much better round for killing deer. Even without a fancy slug gun you should be able to hit one past 40 yards. Slugs will give you big holes with lots of blood, deer are much easier to track than one hit with buckshot.