Ammunition For The Self-Defense Firearm
in February of 2006 I took the liberty of revising some sections in minor ways to keep them up to date and to include recent information. Enjoy Ammunition For The Self-Defense Firearm
Order Page for Bullet Penetration: Modeling the Dynamics...* - by Duncan MacPherson
The article you cited may be a bit more recently updated, but since it bases its conclusions on faulty methodology, it is largely irrelevent.
The links I posted deal with the dynamics of wounding mechanisms. Those do not change with time. Your article is based on data collected from shootings based on the reaction of gunshot victims when they realize they have just been shot.
Your data was collected simply by noting that if it 'stopped' an attack, then it was counted as an effective round. If the attacker was not incapacitated, then the characteristics of the round were ineffective.
This is faulty methodology. No serious researcher of terminal ballistics would include data such as "91% one-shot-stop," without regard as to which internal structures are hit. Certainly, a hit to the heart or other vital organ is usually much more reliable than a hit to the bowels of the lower abdomen, but data was collected using just one solid hit to the abdomen and then judging which caliber or aspect of exterior ballistics was most effective in producing this "stop."
You see, there are two ways in which projectiles incapacitate human aggressors: Psychological and physiological.
As mentioned, psychological incapacitation is the emotional state the target is in when he realizes he has just been shot. He may have any number of reactions to being shot. He may fall down, he may run away, he may surrender, or he may continue to advance, etc.
Psychological incapacitation will vary from one person to another. If he is a reluctant attacker, he may run away or surrender if he is hit in a non-vital area, or he may fall down even if the bullet missed him entirely. Drug or alcohol use, or just the sheer will to keep fighting may influence the target's reaction to being shot.
Obviously, this is not a reliable way to predict a bullet's effectiveness. What may incapacitate one person may not work at all on another.
No aspect of exterior ballistics from a common self defense handgun caliber can reliably "induce" a psychological stop. It is solely the reaction that the target has to being shot.
The other wounding mechanism is physiological incapacitation. This kind of incapacitation is based on shot placement and penetration deep enough to disrupt vital organs or blood loss. This is the only reliable way to "stop" an attacker.
It occurs fastest when the Central Nervous System is disrupted to the point that it can no longer tell the body what to do and the attack is stopped immediately. It does not matter which caliber, bullet style or how fast the bullet was going. If it penetrates deeply enough to disrupt the CNS, it works.
However, in the dynamics of a gunfight, disabling hits to this area (brain, upper spinal column) are difficult at best.
If the CNS is not disrupted, the only other ways to physically incapacitate the attacker is by disrupting vital organs or blood loss. But this takes time. A determined attacker may take 20 seconds or so to cease hostilities even if the heart is destroyed by gunfire.
Shot placement and penetration are the most important aspects of self defense ammunition, not the kinetic energy levels of the cartridge as implied in your article.