If you asked a group of bow hunters how they would prefer an animal to be standing for an ideal shot, 98% of them would probably say slightly quartering away. Standing broadside would be second, but the overwhelming choice would be slightly quartering away, with the emphasis on slightly. A steeply quartering away animal has a very small target.
To demonstrate, hold your phone in front of you as if you were viewing the screen. Now, keeping it on the same horizontal plane, rotate one end of the screen away from you, notice how the horizontal surface area you can see gets significantly smaller. If this were a deer, any miss 2 inches the right or left can now end up in the hind quarter or front shoulder. Compare this to a broadside shot where a miss 2 inches to the left or right will still hit the vitals in most instances.
When you stop to think about this, this is why a slightly quartering away shot really makes sense for bow hunters because the animal is exposing more of its vitals. The main reason for this is because the front side shoulder is now forward, thus, opening up more of the lungs, heart, and diaphragm to be sliced by an arrow. The biggest obstacle for a well-placed arrow will always be the front shoulder. The front shoulder is large enough and strong enough to stop a blazing arrow in its tracks and all you’ll be left with is a short blood trail and a sleepless night.
The worst part about hitting a buck or any game animal in the shoulder is that it wasn’t necessarily an awful shot, and more than likely, an inch or two to the left or right could have made all the difference. Anything behind the front shoulder is pretty soft and an arrow will zip through relatively quickly, hence why most bowhunters prefer a slightly quartering away shot. In contrast, a quartering too shot is very difficult because due to the angle, the front shoulder is basically covering up the entire vital area making an extremely small target for any shooter.
In the video, professional archer, David Houser, demonstrates how and where you should adjust your aim on a quartering animal. Basically, on quartering game, you want your arrow to come out in the off-side shoulder. In order to do this, you’ll want to adjust your aim back towards the mid-section depending on the steepness of the shot, thus, lessening the chance of hitting the front side shoulder. A well placed shot will angle up through the vitals and lead to a very quick and ethical kill.