When people start to shoot gellatin, plumbers' putty, modeling clay and soggy phonebooks they are seeking a magic bullet. They are looking for the perfect round to carry in their guns. Trouble is that there is no such thing as a perfect bullet. The key to most successful police shootings is shot placement. The weight of the round and the type of bullet, hollowpoint versus ball ammunition, is not as important as the well placed round.
Any caliber of bullet can be effective if it hits the right place in the human body. So this now means that we must re-evaluate our tactics and our shot placement to make our bullets do better work. Earlier this year one of my former police students was involved in a situation where he was attacked by a man with a sword and a knife. The officer fired one round into the attacker's chest and another round into the attacker's head. Those two rounds ended the attack because they were well placed and they did what they were supposed to do: they stopped an attacker.
So, when I teach on a range I stress two main things: 1. accuracy of fire and 2. a combination of head and body shots at very close range. Once the shooter gets to feeling comfortable with his shooting accuracy then we practice, practice and practice 2 shots to the chest/torso and at least 1 shot to the head. If things really get stressful then I teach my shooters to go directly to a precision head shot. But accuracy of fire, learned from lots of practice, is what allows people to make precision shots over and over whether on a range or when in an actual attack.