Thankfully, that tough doe ran out of blood and went down, but I was young and that was the sort of aim point everyone was taught. I now subscribe to what the great writer John Wooters called the grapefruit. Imagine a grapefruit suspended between the front legs, one third to half way up from the bottom of the chest, and aim for it no matter the angle the animal presents. This targets the heart/lung area pretty well. Works for me.