| The Kill Shot:
The most humane place to shoot a deer with any gun with reasonable accuracy isn't the heart or lungs but an area approximately 4 inches in diameter above the heart.
An expanding bullet by-passing the heart and cutting through this approximately 4 inch diameter area will nick or damage arteries and blood vessels causing immediate and massive hemorrhaging, the deer's blood pressure drops rapidly and renders it unconscious after a few seconds. The deer's heart will continue to pump blood out of these wounds "non-stop" until it finally succumbs to its arterial damage. This is a very humane kill shot and one that "bleeds out" the deer at the same time.
The heart is a major organ and is the center of the deer's circulatory system, which is surrounded by the lungs which is a major organ and is the center of the deer's respiratory system, this same area contains several major arteries and many blood vessels.
An adult deer’s heart is about 5 to 6 inches long and 4 inches wide and lies low in the chest cavity, lying just above the brisket and behind the front leg.
The lungs are nearly centered in the diaphragm and have an inflated diameter of approximately 8 inches.
The Aiming Point:
You must aim precisely at an intersecting point that uses the deer's front leg as a vertical line and half way up the deer's body for a horizontal line. At this crossing line intersection, a projectile will pass through a triangular shaped area formed by the deer's front shoulder blade and front upper leg bones and not hitting any of these bones. The only bone hit in this 4 inch area are rib bones, directly behind these rib bones are the center of the biggest part of both lungs (respiratory system) and the large arteries at the top of the heart (circulatory system). By effectively shutting down the deer's (respiratory system) and (circulatory system) with one precise shot, death for the animal is immediate and without suffering.
The picture below will show this aiming point.
Margin Of Error:
Nobody places a bullet precisely every time, so what is the margin of error when not hitting this zone exactly where you wanted to. The three dots on the above pictures represent projectile impact points, the large dot is the upper-most part of our desirable 4 inch triangular shaped target zone or aiming point, the smaller bottom dot is the lower-most part of the 4 inch triangular shaped target zone, projectile impacts here result in both, arterial heart and lung hits. The upper smaller dot represents a high impact point that will hit the deer's spinal cord, the animal will go straight down and be paralyzed it will then need a follow-up shot placed in the kill zone. A projectile impact several inches back still damages both lungs, however, as the distance increases from the heart there is less air-pressure in the lungs and a deer can travel great distances or possibly survive a lung shot placed too far back.
The Big Picture