What do you mean by "drop?" I think you should clarify. I shot to the spine in the lower back will definitely "drop" an attacker but it will not incapacitate him. A person unable to walk is still very able to shoot back. The only shot that instantly incapacitate an attacker is a shot to the brain stem or the top roughly 10% of the spine.
I agree with everything else you said and I'm sure you knew what you're talking about I just thought clarification was needed.
You are making a particular point and I will be more specific. Getting shot in any part of the spine will make any person "drop". However, shot into the thoracic or lumbar section will more than likely just paralyze the person being shot. And while in considerable amount of pain, if the paralysis is only from the waist down (which is more likely in the lower parts of the spine), the gun shot recipient could indeed still return fire.
However, if the shot was to C1-C4 along the high cervical nerves, the person afflicted with the GSW will at minimum be paralyzed from the neck down and therefore "drop" immediately. However, with something as invasive as a GSW, will more than likely die quickly due to a number of reason: nerve communication that controls breathing, nerve communication that controls the heart, never communication from the brain to the rest of the body's functions.
If the shot was however, between C5-C8 in the neck, then more than likely there will be massive paralysis (neck down or upper body down). The other thing to consider with a shot in the neck, is that if the bullet doesn't hit the vertebrae squarely, the bullet can fragment. There are many vitals within the neck area (trachea, arteries, veins). Any of these being hit will usually cause fatality but NOT in a "drop" capacity as the OP was asking.
So, from this, what does a person defending himself with a firearm need to learn to do? As stated previously, be prepared to shoot CofM until the threat stops. I've known no one good enough at shooting, to be able to, under pressure in a life or death situation, place a well aimed shot to the C1-C4 High Cervical Nerve area, especially to a moving target. Therefore, multiple shots, CofM until the threat stops. If the CofM shots are doing nothing (person may be wearing body armor), then shoot to the ocular cavity. This is a boxed region from the eyebrows, eyes wide, down to the middle of the nose. Any higher and the bullet will ricochet upward, any lower and the bullet will miss the brain.
I know this is a rather gruesome response. However, to stop the threat of being killed, one needs to know where to place their shots.
