I aim for the heart on a close up, slam dunk, broadside shot. When I say close up I mean 15 or less. Anything beyond that I'm aiming for a center of mass hit. That said, sometimes you because of the nervousness of the deer and all that, I aim for the heart knowing the bugger is going to drop. On a quartering away shot it just depends on the angle and how severe it is. I just usually aim on a quartering away shot to hit the far shoulder or where the back of theleg meets the chest. Gives me the biggest margin of error. I should get both lungs or liver lungs or liver both lungs or some combination there of. If I hit the heart on a quartering shot I made a bad shot.....well I didn't hit what I intended to. Here's a 22 yard shot that hit where I aimed. I've had several like this, but this one is cool.