I train to aim for the heart and use clothed 3D targets, but I'm sure I'm the minority. The heart is only slightly offset to the left, it does straddle the midline of the body. So, for a perfect frontal torso, aiming centered horizontally and vertically center sternum (just above the nipple line) will hit the heart. Many human type targets with a high chest vital area have the heart in about the center of the aiming point.
My favorite non-3D targets are photo realistic ones with a faint outline of the organs that you can't see more than a few feet away so you are just shooting a photo-realistic armed, clothed person. They make them posed at different angles, so this is a cheap and easy way to practice hitting vital organs (heart and midbrain) at various angles.
I'm talking about rapid shooting a couple bullets a second also, not taking careful deliberate aim at a bullseye. Flash front sight and fast trigger press straight back, follow through/reset/repeat.
My favorite non-3D targets are photo realistic ones with a faint outline of the organs that you can't see more than a few feet away so you are just shooting a photo-realistic armed, clothed person. They make them posed at different angles, so this is a cheap and easy way to practice hitting vital organs (heart and midbrain) at various angles.
I'm talking about rapid shooting a couple bullets a second also, not taking careful deliberate aim at a bullseye. Flash front sight and fast trigger press straight back, follow through/reset/repeat.