The same circumstances that forced the FBI to seriously reevaluate their needs and quantify questions like "what is stopping power?" force us to ask those same questions as well.
Prior to the 1986 Miami shootout the FBI had already done what they thought the needs of LE were and they had the answer to "what is stopping power". They had the scientific approach.
Prior to Miami the FBI had developed their Computerman Model. At that time they were preaching that rapid expansion, limited penetration was what was needed for stopping threats. Their Computerman Model was basically the old RII formula. They were absolutely sure that formula was what was needed.
In 1980 we had been issued, for a very short time, the same W-W 115 gr Silvertip ammo that was used by the FBI in Miami. We had some people who were making the ammo call who went along with the FBI and their Computerman Model, ie, rapid expansion, limited penetration. We had only carried that round a few months when 2 of our Troops were in a shootout with a Chicago biker gang member. They hit the biker 11 times COM at a distance of just a little over the length of the squad car. None of the 11 rds penetrated deep enough to reach the vitals. The biker emptied his 5 rd revolver, missing our Troops but fell over dead. Not from any of the bullets tho. He died of a heart attack from the stress of being shot at. Seems his life style had not been a healthy one and he had several major clogged arteries that did him in. It wasn't a Silvertip that killed him, it was bacon cheeseburgers.
The Silvertip did not fail. Every Silvertip performed exactly like it was designed. Rapid expansion, limited penetration. It was just the wrong design for what was needed. Within days of the shooting we had pulled all the Silvertips from our Troops.
Now fast forward a couple of years. The FBI was going to 9mm. They were still preaching rapid expansion, limited penetration, and singing the praises of the Silvertip. A couple of guys from our main range loaded up the investigation file of the biker shooting and drove to Quantico to meet with their range people. Our people showed them the results we had seen. The FBI said they didn't care. They had their Computerman Model which showed that rapid expansion, limited penetration was what LEOs needed to stop a fight. They blew off our results as anecdotal. Their Computerman Model was more accurate. Our guys packed up our file and came home.
Unfortunately for the FBI several months later they learned about the Silvertip like we had 6 years earlier but they had more tragic results.
It was after Miami that the pendulum at the FBI swung to the other side. They then became advocates of all about penetration, expansion little or no importance. Eventually their pendulum swung more center line.