Eaton Rapids Joe talked about it yesterday. In 1986, eight FBI agents got involved in a shootout with two very bad actors, and changed the way police look at firearms, tactics, ammunition, and equipment. The aftershocks of that fight were seminal to how law enforcement looks at fatal encounters.
At the time I was a young peace officer and I remember reading the reports, following the FBI testing and trying to digest the data that came out for several years There were some interesting things that came out of that event and the subsequent reassessment.
The 10mm cartridge. The 10mm is a direct result of the FBI testing that followed the shootout. The problem is that most people can't handle it, it's a high energy cartridge designed for semi-auto handguns and is more demanding than the vast majority of folks find it uncomfortable. That, and it beat the early guns to death. Handguns designed for it seem to do okay, but it is tough on handguns. Interestingly, the .40 SW cartridge is the little sister of the 10mm. Many cops carry a .40 SW today, and we never heard of it before the shootout.
Better bullets. The FBI tested a lot of bullets in the aftermath, and the bullet manufacturers paid attention. There were some startling things learned, and for a while, it seemed that everyone was testing bullets. We started learning about things like tissue displacement, penetration, wound cavities and how bullets acted when shot through various mediums. The result of all that testing and evaluation is that we have a better understanding of terminal ballistics and we have much better bullets, across the board, than we had in 1986.
We also learned that the old things work. The fight, with all its savagery and horror was ended by a determined FBI agent shooting a revolver. Probably using the FBI standard load, which was a .38 Special +P load. Sometimes good enough is good enough.
It's been over 30 years since that fateful day in Miami, and lots of things have changed in police work and in the gun community in general since that time. A lot of it came out of that day in April 1986.