I agree with many of the points made by the FBI in their decision. But do not come to the same conclusion for MY personal needs. And, they fail to address a significant element - busting through barriers and busting through bone obstacles.
And I see nothing in the FBI rationale to motivate me to sell my 10mm, .45auto, and .40S&W semi-auto pistols. (I'm not selling my 9mm pistols, either.)
The FBI bases it's penetration and expansion comparison on ballistic gelatin with one or two layers of denim. Unfortunately, that is an exceptionally imperfect model of the human body or an animal's body. Experienced hunters will know this better than anyone.
While the best 9mm of premium defense ammo may perform somewhat similarly (though not exactly as well) as .40 and .45 in ballistic gelatin, the greater ability of the heavier .40 and .45 caliber bullets to smash through harder obstacles and bone is a factor.
This doesn't mean that I wouldn't trust, nor carry a 9mm pistol, as I do, on occasion, when I need to carry a really small pistol.
I don't think 9mm is necessarily a bad choice for law enforcement or military, particularly since so many LE shooters are "struggling shooters" who get very little practice. Capacity is important and so is ease of handling recoil. 9mm has capacity and clearly is easier for "struggling shooters" to handle. And it can reasonably be rationalized and said that it is "good enough" for agency use, particularly where budget is a major driver in the decision!
So, I don't think 9mm is a terrible move for LE, but it's not necessarily a good move for me as a civilian well familiar with shooting various calibers and who practices regularly.
As the article mentions, Glock 40s were the pistols that struggling shooters were having a hard time with. Part of this is the platform itself. Forty caliber Glocks, especially the G23 and the G27 are especially snappy. And even MORE so with 155 gr. and 165 gr. ammo. Other platforms (Browning HiPower, M&P, Sig P320, HK VP40, etc.) handle .40 caliber much more comfortably and "softer" than the Glock forty caliber models do. And selecting 180 gr. ammo in .40S&W caliber also provides a softer felt-recoil. These are significant factors which were not addressed in the "report"!
For the regular civilian who can choose the best platform for themselves as well as the best caliber for themselves, following the FBI in lock-step doesn't make any sense. Though it might for newbie and "struggling shooters".
For an experienced shooter who is skilled and practices regularly, choosing .45auto or .40 caliber in a platforms like the M&Ps, HK, and Sig P320s can make plenty of sense. If not, I guess we all need to sell all the pistols and calibers that we own and just buy Glock 17s and Glock 19s. No point in having, nor relying upon anything by 9mm, eh? Not!
I like the G17 and the G19 and shoot them. Same with the G21SF and G30. I've used these guns for years. I also have a G23, a G23 Gen 4, and a G22 Gen 4. Compared to the M&Ps, Browning HiPowers, VP40, and Sig P320s (all in forty) I find the Glock forty caliber pistols to be harsher and "sharper" in recoil.
For carry and defensive use, I prefer 180 gr. HST in .40 caliber, with an M&P40, M&P40C, or P320 platform. I shoot these pistols well in this caliber; they are soft-shooting and easy to shoot, and they don't lose much capacity to 9mm. What they do offer is a greater ability to bust through heavy bone, such as is likely to be encountered by the outstretched arms of an assailant, coupled with heavier clothing, and breastbone - other obstacles like glass, and in defense of animals who have plenty of heavy bone to deal with, as well. .45auto and .40S&W can outperform 9mm in penetrating these and other obstacles.
A real human adversary, with arms outstretched in front of himself, presents a far different set of target characteristics than a block of jello with two pieces of denim on front of it.
Those who choose to carry 9 (rather than 40 and 45) are certainly free and welcome to make this personal choice. I don't mind at all. If you are happy with it, then I am content and happy for you!
But 9mm is not MY first choice in a defensive pistol caliber, regardless of what the bureaucrats decide to choose for the men and women who go into harm's way every day to serve and protect us. I know there are many LE personnel who would not be happy about having to move to 9mm.
I put more faith and trust in a heavier bullet (180 gr. or 230 gr. HST, Gold Dot, Ranger, etc.) carrying more momentum to bust through bone and obstacles. And I shoot them enough to be competent with them. I happen to be among those of us who are not "struggling shooters" under a government agency directive.