The 10mm Auto pistol round has been controversial almost since its inception back in the early 1980's. It's more powerful than the famous .45 ACP, and appears to be at least as (if not more) effective than the latter when a suitable defensive bullet (i.e. hollow-point) is used. It has the big advantage that the same size pistol can carry more 10mm rounds than .45's. However, it also kicks harder and is less controllable by the average shooter, particularly in rapid fire. I'm not going to go into all the details here. If you're interested, consult any or all of these articles:
At present, only a relatively few enthusiasts carry the 10mm for personal protection. However, two circumstances are causing shooters I know (and myself) to reconsider that. Sure, the round has its disadvantages, but the changing threat environment means that its advantages may now outweigh them.
Firstly, we have the growing phenomenon of urban crime and unrest in the form of "flash mobs" or extremist demonstrations (a.k.a. "riots"). We've discussed criminal flash mobs here on several occasions. They've now developed into organized shoplifting gangs and mobs of hoodlums, assaulting not just specific stores but entire shopping districts, sometimes hitting several stores at once. If you happen to be shopping in the area at the time, don't expect the cops to be there to protect you. They'll either be keeping clear, under orders from politically correct District Attorneys and city leaders, or they'll be swamped with incidents all over the place, so that you have to wait your turn. As for rioters and "demonstrators", we've already discussed the threat they pose to our neighborhoods, added to which is the fact that in many cities, they're a protected species; they're allowed to get away with their criminal behavior, while those seeking to defend themselves against it may be officially targeted. See these two articles:
For the most recent example of such politically correct prosecutions, see here. It's a travesty of justice - for heaven's sake, the shooter had already been found by a police investigator to have acted in legal, legitimate self-defense! - but when you get a rogue, politically motivated D.A., all bets are off. I hope and trust that the jury will dismiss the prosecution for what it's worth - namely, nothing at all.
In so many words, if you're confronted by multiple criminals, you may (and probably will) need multiple rounds to deal with them. A pistol chambered in 9mm Parabellum, the single most popular handgun round in the USA and worldwide at this time, certainly has sufficient magazine capacity to provide those multiple rounds; and, if an effective defensive bullet is used, will probably be successful in most cases - but not all, because there's another factor that enters into the equation. That factor is illegal drug use.
The drugs available "on the street" have typically not enhanced criminal performance during the commission of crimes, with the exception of the notorious PCP (a.k.a. "angel dust"). I had occasion during my work as a prison chaplain to deal with PCP addicts, and the effect of the drug on their psyches was staggering. Many of them were left permanently mentally impaired, and were unpredictably violent, aggressive and confrontational.
Sadly, today other drugs are coming to the fore that have an equally devastating effect on those who use them, particularly when they're mixed together. Fentanyl is being combined with synthetic marijuana (a.k.a. "spice"), methamphetamine, cocaine, heroin, etc. to produce far more dangerous behavior and behavior-altering effects than with the latter drugs alone. Veteran street cops with whom I've had contact tell me it reminds them of the earlier PCP plague. In particular, they're finding that felons shot with a 9mm pistol are simply not being stopped fast enough to prevent them causing serious injury or death to their victims, because the round isn't causing enough damage to put them down rapidly in their chemically-'enhanced' state. One of them wrote (I paraphrase it below, to clean up his language):
Our department mandates that we carry a pistol chambered in 9mm, but we're allowed to carry any backup weapon of our choice, provided we can qualify with it. I and a few others have switched to Glock 29's, chambered in 10mm Auto, for our backup guns. If we meet up with one of these drugged-up guys, we reach for our backup gun even before our 'primary' weapon, because we know we're going to need something more powerful than a 9mm to stop him.
There are those who'll argue that more accurate shot placement would allow the smaller round to perform just as well as a larger one. That's fine in theory, but when you've got a moving target (the perpetrator) closing on you rapidly, possibly with a weapon in his hand, and you're moving to avoid his attack, and your stress and adrenaline levels are off the charts . . . it's a whole world away from shooting slowly, calmly and without stress on the square range at paper targets that don't move and aren't threatening you. Some (very few) shooters can perform as well under such extreme stress as they do during training. Most of us can't. We should expect to be less accurate - which places more of a burden on the rounds we're shooting to do the best job they can when they hit whatever they hit.
I know many shooters blindly trust the "official" figures, charts and data, which claim that a quality 9mm hollowpoint will deliver as much expansion, penetration and energy as a bigger round. They're right, on paper. However, real life doesn't take place on paper, and drug-addled criminals can and will make a mockery of what "the book" says should happen when they're shot. I discussed this issue in an article some years ago:
Bullet and cartridge effectiveness for self-defense
If you didn't read that article at the time, I strongly suggest that you click over there and read it now. In particular, read the whole thing, not just the beginning. There's a lot of "meat" in there, and it's all important. In brief, size (projectile cross-section, bullet weight and overall expansion potential) does matter; and bigger bores have benefited from the same technological advances that have improved the 9mm. They've all gotten better than they were.
In brief, due to the possible need to repel multiple assailants, cartridge capacity is important. While the 9mm is champion in that regard right now, the 10mm (and its smaller cousin, the .40 S&W) is pretty close on its heels, and all of them usually outperform the venerable .45 ACP. (For example, comparing full-size models, the 9mm Glock 17 holds 17+1 rounds; the 10mm Glock 20 and the .40 S&W Glock 22 both hold 15+1 ; and the .45 ACP Glock 21 holds 13+1.)
On the other hand, there's the need to hit a potentially hopped-up assailant as hard as possible, to make him cease his attack on you. The 9mm is no slouch, but it hits less hard than the .40 or .45 - and the 10mm outperforms all of them, if a full-power round is used.
So, with the 10mm Auto, you have a lot of power - probably as much as a good shooter can control in accurate, high-speed firing - and a higher-capacity pistol. That combination is looking increasingly like a winner in today's self-defense environment.
I'm testing some Glock 10mm's right now, and I'll report back on how I find them in some practical, real-world-related shooting tests in due course. I'm sure my disability and pain level will make it a difficult exercise. To help with that, I'm trying a few aftermarket accessories like a heavier tungsten recoil spring guide rod, combined with a stronger spring. Are they worth it? (To be answered in the context of another question - "What's my life worth?") Are the advantages of the more powerful round worth the pain it'll cost me to use it? We'll see.