The level of interest in these threads always amazes me.
This should matter to about 12,000 FBI agents and a couple of hundred FBI uniformed police. We don't issue ammo to any other agencies. NYPD, Chicago PD, and the East Bumfudge Heights Sheriff's Office can still issue and carry whatever ammo they like.
This has nothing to do with small guys and females ("runts and *****" in the vernacular) not being able to qualify. After 21 weeks in the Academy, where a New Agent fires about 10,000 rounds, you can either shoot or you don't graduate. I was a Bureau Firearms Instructor for about 15 years - our people can shoot.
Its about money. 9mm is cheaper, its easier on the guns, and according to our ammo gurus it is just as effective as anything else. So why pay more? Its your money we're spending after all. And this is from a guy who paid his own money 23 years ago for a Sig P220 and has carried it ever since. (I just found my first paystub going through some stuff. I took home $846. The Sig was $533. The Mrs was not happy.)
Guys with .40s will keep their .40s unless they want to switch. New guys will get 9mms. Old farts like me and SWAT guys will still carry .45s or whatever has been grandfathered in. Birds will sing, dogs will bark, and bad guys shot between the shirt pockets will still fall down.
Current issue 9mm (yes, we have allowed 9mms since forever) is the 147 grain Gold Dot. I suspect it will continue. .40 is a 180 grain Winchester bonded JHP. .45 ACP is a 230 grain Golden Saber. 10mm (yep, still have those) is a 190 grain Federal JHP.
I have to carry whatever ammo they give me. Since in my case it is a big fat .45 hollowpoint, I'm fine. (Also, the price is right.) I'd probably be fine with the issue 9mm, too. Other agents are welcome carry the issue 9mm or pony up for a .40 or .45 ACP. But if you don't work for the FBI, why would anyone care?