If you are comfortable with where the gun is shooting and your ability, a high shoulder shot will drop them in their tracks every time but you have a 4" target. To be safe aim for center shoulder, you'll hit bone and muscle there and if they don't drop they'll definitley be stumbling and leaving an easy trail to follow. Better to give up a few lbs of meat than to loose the animal. I seldom find a good blood trail on a lung shot with rifles before I see the animal on the ground, and then it's blood that comes out their nose. Slow down and make sure you've tracked them at least 250 yds. Good luck