If you want to drop a deer on the spot there are only two ways that it can be done.

1. A direct hit to the brain or spinal column. This obviously drops deer where they stand and they expire pretty damned fast.

2. A shot through the lungs AND heart with massive accompanying damage. Imagine a 12 gauge slug punching through the lungs and almost completely removing the heart. The deer wouldn't be able to breathe, and would not have any blood pressure to the brain. My guess is that this would still not kill the deer instantly.

Don't worry about dropping your deer where he stands. Just make a good shot and then follow the red splatters.