9mm is Good Again: FBI Now Says Go for 9mm, Gun Writers now Like 9mm, Lots of approval for the .380

 FBI says 9mm
Admittedly this is a two year old article but the wheels of government move slowly.  If you notice, now the gun press has moved back to the 9mm as a good round for self defense, though not all them.  Many writers who wouldn't have considered the 9mm up to the task now feel that with the momentum moving again toward less is more theory notice what some of us knew all along.  Simply, that 9mm allows more rounds in the magazine, punches a hole much like the vaunted .40 an .45 especially when expanding, and is much cheaper to use for practice.  Also, the price and selection of weapons in 9mm outnumbers all the others.  It is ubiquitous.  The funny thing is that even the .380 is getting some good press now though it's not my first choice for carry it does fill the need for weight and size when clothing limitations exist for concealed carry due usually to summer months.  It also has a superb reduction in recoil yet still punches a hole like the .38 or 9mm, but not as deep with the same expansion.  For that matter, I'm not against a .22 revolver versus carrying nothing.  Often just the presence of a gun will inhibit action from the aggressors and you can't defend against everything.

Just like the diet guidelines have changed every decade or so, the caliber guidelines for self defense and law enforcement handguns is changing again.

9mm vs .40 S&W

.38 Special - it was the standard for almost a century.  The limitation is lack of firepower/capacity versus the civilian options after 9mm semi-auto  pistols become common in various sizes.

9mm -  This is the same diameter as the .38 special but it has less lead in the bullet  but increased velocity making for more energy overall.  It is configured to stack in magazines and feed in a semi-auto pistol.  Limited  defensive loads prior to the 1990's and other perceived deficiencies came to the front after the Miami shootout.  They probably should have considered that rifles tend to beat handguns every time and armed FBI agents with carbines or shotguns in their vehicles in addition to sidearms.  Bureaucrats never see the obvious.  Good ammo might have made the difference as well.  The final item might have been to train them to fight injured since that seemed to be the final issue that caused the loss of the fight.

10mm - So then they picked the big boy gun but had trouble with control.  It had a strong recoil that some shooters couldn't manage well.  Concealment was probably an issue as well.

.40 S&W - This should have been the ideal compromise except for female recruits it was still too much to handle.  Some men found it a problem as well. 

9mm - Back to the past.  With improvements in defensive ammo it may end up being the ideal compromise to include trainees having an easy time with it.  +P and hotter ammo makes it closer to the .40S&W.

What Next?

5.7mm - Were it not for the size of the gun it has even better numbers all the way around.  Capacity 20-30 rounds.  Recoil is nil.  Accuracy is excellent.   Energy is high and penetration is sufficient. Weight is low.  Cost per round is no higher than .45.