9 mm & .40 S&W Remix

Several months ago, I invited the readership of this column to participate in what amounts to a debate. The subject was the status of the two most popular service pistol calibers—9 mm and .40 S&W—and how they compare, why they are chosen. The response was overwhelming and not only in numbers of participants, but also in the quality of their contributions. We heard from many shooters with a variety of carefully reasoned and clearly written comments on their feelings about these two rounds. I truly appreciate the effort that went into this and I hope that all readers who responded would be willing to do so again and on other topics. So, what did we learn?

First, it seems pretty clear that American shooters understand why the .40 S&W was conceived. Pure and simple, the primary intent was to provide law enforcement with a powerful medium-bore service cartridge that would fit into 9 mm-sized pistols. It was always more powerful than the 9 mm. Civilian shooters took to the new round with considerable enthusiasm. However, the range of comments from readers suggested to me that civilian pistol shooters still have some reservations about the .40. Recoil and muzzle blast are never pleasant to deal with and the .40 has plenty of both. Some guys actually dismiss the .40 as being too problematic (in the shooting sense) for everyone in the household to deal with. This was a far stronger belief than I would ever have predicted. While .40s don’t particularly bother me, if the buying public is actually acting on this belief, then that’s the way it is. 

By default, the 9 mm is the next best thing. Everybody likes to do their fun shooting and even serious practicing as economically as possible. A quick price survey of available ammunition was very illuminating.  Boxes of 9 mm ammo can often be found at close to half the price of .40 S&W. This means that people are really shooting their personal protection guns often enough that the cost of ammo is very important. This is sometimes true of shooters who carry guns on the job or teach shooting skills professionally. In effect, the popularity of 9 mm is at least partially because you can shoot a lot more for the same money. This reasoning cannot be faulted, because in crisis shooting, a hit with a 9 mm is superior to a miss with a .40. You need to shoot as much as possible in practice. But in the final analysis, there is no substitute for horsepower. 

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10 Responses to 9 mm & .40 S&W Remix

BigFoot wrote:
March 01, 2013

We might as well finish this discussion by clearing up the question of "over penetration." Again, here is the FBI's thinking on the subject. "It is essential to bear in mind that the most critical factor remains penetration. While penetration up to 18 inches is preferable, a handgun bullet MUST reliably penetrate 12 inches of soft body tissue at a minimum, regardless of whether it expands or not. IF THE BULLET DOES NOT RELIABLY PENETRATE TO THESE DEPTHS, IT IS NOT AN EFFECTIVE BULLET FOR LAW ENFORCEMENT USE. An issue that must be addressed is the fear of over penetration widely expressed on the part of law enforcement. The concern that a bullet would pass through the body of a bad guy and injure an innocent bystander is clearly exaggerated. Any review of law enforcement shootings will reveal that the great majority of shots fired by officers do not hit any bad guys at all. It should be obvious that the relatively few shots that do hit a bad guy are not somehow more dangerous to bystanders than the shots that miss the bad guy entirely. Also, a bullet that completely penetrates a bad guy will give up a great deal of energy doing so. The skin on the exit side of the body is tough and flexible. Experiments have shown that it has the same resistance to bullet passage as approximately four inches of muscle tissue. Choosing a bullet because of relatively shallow penetration will seriously compromise weapon effectiveness, and needlessly endanger the lives of the law enforcement officers using it. No law enforcement officer has lost his life because a bullet over penetrated his adversary, and virtually none have ever been sued for hitting an innocent bystander through an adversary. On the other hand, tragically large numbers of officers have been killed because their bullets did not penetrate deeply enough." I think we can summarize FBI doctrine by saying go deep and go big. Only one or two of your shots will end up hitting the bad guy so you have to make them count.

BigFoot wrote:
March 01, 2013

Rob raises some interesting questions. Smith & Wesson gave a 40,000 round warranty on the slide and frame of their M1076, enough to last the average Agent through his 20-year career. That was with the "Lite" stuff. Additionally, S&W initiated a program to fire a M1076 to destruction with the hottest commercial ammunition on the market (Norma). After approximately 18,000 rounds nothing was broken and the test was discontinued. Here is the FBI's thinking on shot placement. "Shot placement is obviously critical, and our test criteria presume that the shot is placed in the vital area of the body, which contains the brain, upper spinal cord, heart and aorta/vena cava. This area runs from just above the eyes to the diaphragm, and is about 4 inches wide. But, as our experience in Miami amply illustrates, shot placement is only the first part of the equation. Bullet performance is critical to translate shot placement into an effective, incapacitating wound. If shot placement was all that mattered, we could arm all Agents with .22s. Secondly, perfect shot placement may be difficult to attain in the stress and dynamics of a shooting incident. The larger calibers offer a 'margin of error' in that where a smaller bullet may just miss the aorta, for example, the larger one in the same placement will damage it. Shootings are characterized by their sudden, unexpected occurrence; by rapid and unpredictable movement of both officer and adversary; by limited and partial target opportunities; by poor light and unforeseen obstacles; and by the life or death stress of sudden, close, personal violence. A review of law enforcement shootings clearly suggests that regardless of the number of round fired in a shooting, most of the time only one or two solid torso hits on the adversary can be expected. Given the idea that one or two torso hits can be reasonably expected in a handgun shooting incident, the ammunition used must maximize the likelihood of immediate incapacitation."

Rob wrote:
March 01, 2013

I remember that another problem the FBI had with the 10 was that the S&W 1076s didn't hold up as well as planned. In addition, they were a large package. There could be a whole 'nother debate as to whether 9 mm frames hold up to the battering of the 40. I also seem to recall that the FBI agent who ended theMiami gunfight started carrying a 45 afterward. Yes, ammo has improved since 1986, but the most important thing is still shot placement. While I prefer a 45, I can see a lot of reasons for shooting a 9, including cost off ammo. Until recently I was an advocate of a 22 for practice, but you can't find much of that right now.

BigFoot wrote:
February 27, 2013

Penetration vs. expansion. Is it possible to have both? The FBI knew that they could improve penetration by increasing bullet weight and/or velocity. But, increasing velocity could increase expansion which decreased penetration. And was the bullet going to take an easy path through soft tissue or was it going to smash through bones? The FBI had a conundrum. Like Pete points out, you never know in advance if you are going to need penetration or expansion. Since the search for a new cartridge was initiated by losing agents to under-penetration, their new round was going to have penetration, and lots of it. (FBI: "We are aware of numerous instances of Agents/officers being killed because their round did not penetrate enough.") They also knew that incapacitation had to do with blood loss so large holes counted. Here is the test the cartridges had to take and the results: 1. Success rate of meeting 12" minimum penetration (12" was the absolute minimum and 18" was preferred). 2. Wound volume (cubic inches of tissue disrupted). 3. Average penetration. The results were: .38 Special +P 158-grain lead hollow point 67.5%; 2.16; 11.76/ 9mm 147-grain jacketed hollow point 67.5%; 2.82; 13.84/ .45 ACP 185-grain jacketed hollow point 92.5%; 3.98; 19.95/ 10mm "Lite" (40 S&W) 180-grain jacketed hollow point 97.5%; 4.11; 17.90. Too bad we don't have the results of the full-power 10mm, they would have been awesome. As you can see, the numbers favored the 10mm Lite (.40 S&W) and the .45. It was a toss-up but the 10 got the nod due to more magazine capacity, better accuracy, and a tad less recoil. A logical person looking to buy a pistol for self-defense would examine the numbers and buy the caliber that gave him the best odds of winning. We all look forward to articles such as this one because we all have our favorite caliber and we like to express our feelings of why. But at some point the numbers have to be revisited because they tell the truth, they just don't give an opinion.

Pete wrote:
February 26, 2013

In the 1986 Miami FBI shootout, one of the badguys was struck with an agent's 9mm Winchester Silvertip round (which at that time was THE caliber and THE bullet according to the "experts"). The bullet was headed straight for his heart, but expanded and stopped short of killing him. If that round had reached his heart, it would have stopped him from slaughtering those agents in the next few minutes. So the obsession became "If only that round had more penetration!" What we really need to remember, though, is that if the opposite had happened, if a bullet penetrated and just missed his heart and they said "If only it had expanded more, it would have hit his heart and stopped him!" then the obsession would be for more expansion...

Rich wrote:
February 26, 2013

Unliked by some, my m&p comp .357 sig w/10 rd mags. provides my peace of mind. But, the simple truth for most is we have limited wardrobes and limited bank accounts. Exotic rounds might stir the imagination but being good with what you have is the ultimate self defense.

John wrote:
February 26, 2013

No no, the reason I like the 9mm over the .40sw is one there’s more rounds on tap, and violent encounters tend to involve multiple strings of fire More rounds is a very important issue. Seconded, the 9mm is a very mature round, universally used around the world for a handgun round. Also, because it’s been around so long; the 9x19mm has been almost push to the limit in terms of ballistics that the round can take. Recoil isn’t much of an issue here when shooting a .40sw vs. 9mm.

BigFoot wrote:
February 25, 2013

A B See, you are right about the 10mm preceding the .40 S&W. After the 1986 FBI Miami shootout, it was decided that the 9mm and .38 Special were just too under-powered for the FBI so they set out to find a more powerful cartridge. While they valued expansion, for obvious reasons, expansion reduced penetration. And penetration in bad guys was the most important criteria they had because they wanted to shoot through clothes, ribs, sternums, outstretched arms, anything that got in the way. To say that they were obsessed with penetration would be an understatement. (have you ever wondered why the ballistic gelatin test, showing penetration in "soft tissue," never has any "bones" in front of it like in a real person? That would alter the results and we should be aware of that. Maybe we need more penetration and don't know it.) The one they fell in love with was the original 10mm which launched a 200-grain bullet at 1200 fps, certainly enough gun to solve all their problems, both real and imagined. It was declared "the best law enforcement cartridge available" and was served up in the Smith & Wesson Model 1076. Almost immediately, it was evident that they had too much of a good thing for the average shooter so the "FBI Lite" was developed, a 180-grain bullet at 980 fps. Smith & Wesson quickly figured out that they could cram that kind of performance into a 9mm frame and the .40 S&W was born. The full-power 10mm is probably the best-kept secret out there for self-defense, assuming you are man enough to master it.

A B See wrote:
February 23, 2013

I thought that the 40 S&W was developed because smaller framed men and women couldnt handle a full-house 10mm Norma. The feds needed those people to qualify with the 40 which was nicknamed the 10mm lite. Saying that the 40 came first is revisionist history in my opinion. Ymmv.

BigFoot wrote:
February 22, 2013

In rereading your original article, the comments in favor of the 9mm were: lower cost of ammunition; less recoil; today's ammunition is better. So let's take those arguments one by one. Cost: Sure, you can save money on the 9 but what's your body worth? If you put a couple of 9s in the bad guy and he's still standing, are you happy because you're saving money? Buy a .22 if you want to practice. Recoil: I have a Kahr P40 (.40 S&W) and the recoil really beats my hand up. I bought it because it was small and light for carry and fired a cartridge with more life insurance than a 9mm, not because it wouldn't hurt a little after 25 rounds at the range. If you need a house gun, just buy a .40 with more weight and size. Ammunition: The ammunition/bullet manufacturers finally solved the problem of how to make bullets expand. But as they expand, they have more frontal area and lose penetration. Anyway you cut it, an expanded 9 isn't as good as an expanded .40. The only excuse for owning a 9 is because it represents the maximum amount of pain that is tolerable while firing a magazine full. Notice I used the word pain instead of recoil. A gun that simply bounces when you fire it doesn't mean it hurts; that just makes it scary like an "assault" rifle is scary to some people. We are talking about self-defense here, the art of saving your butt, not fun at the range. And as far as "getting back on target" so you can fire-off the remaining rounds in your magazine, try getting better with your first shot. Why? Because while you are saving money by firing all that cheap 9mm ammo, the bad guy is firing back at you. I realize that 9mm fans need a lot of convincing to change their minds so just go here: