The last I heard the Failed Bureau of Investigation, in 1986 after the disasterous shootout, went to 10mm, because the bank robber was shot in the chest with their "then current" best 9mm ammo. The perpetrator was an ex-army ranger and he lasted 90 seconds, enabling him to kill several agents and wounded just about all of them... he had a rifle in 223 mini 14, I believe.
Then agents couldn't handle the 10 mm well, so next, the FBI went to the 40 S&W.
Agents were still missing the target, alot.
More hits in target were better than missing it completely. So back to the 9mm. I believe they use 147 gr Speer Gold Dot for the desired penetration, and more hits on targets for their agents.
For you girls, ...the 380 ACP gets a bunch more hits on target than 9mm,... hits are better than misses.
There are a lot of clowns in law enforcement, as the video shows.
That's why they send out the swat team if any gun play is expected, the suits don't want to get dirty, let alone shot at or killed, as it's a government career, for most, who never have to draw their duty weapon to deter a threat, in a lifetime of government service.
The 10mm had a couple problems…. Recoil was one of them, but cost and the S&W pistol were two of the others.
The move to the Glock and the 40 S&W (short/weak) made the G22 and G23 the standard pistols for a while. In about 2015, the SWAT program moved back to 9mm for the capacity and the terminal performance of the Speer G2.
The current duty round is the Hornady Critical Duty 135grn.