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Very good article comparing 9mm and .40SW for self defense


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Here are some of the snippets that I thought were thought provoking...

I think this is exaggerating the situation. The difference we're talking about is tiny. If my 9mm expands to, say, 0.70" and your 40 expands to, say, 0.80" you've got one twentieth of one inch greater radius, meaning you can be one twentieth of one inch farther away from a perfect shot. Your skill, gun, and ammo will all cause greater variation than that from shot to shot.

Without getting into a debate about energy and its effect on incapacitation, a typical 9mm defensive round has about the same muzzle energy as all but the lightest 40 S&W defensive rounds.

If you feel more confident with a .40, that's certainly your choice. But there's an overwhelming amount of evidence to show that the 9mm is equally effective in practical terms for defensive/duty use. Training is substantially more important, and you can train more with 9mm for the same money.

+1. If you are going to choose between the 9mm and the .40 (you could just get both :-)), you should get the one that you can shoot the most comfortably and accurately, and feel the most confident with.

That said, there ARE a few factual differences that will not absolutely make the decision for you, but that are pretty widely agreed upon and should help you decide. What you DO with these facts, and how you interpret them, depends on your own situation, for example your age and health, how well you can control recoil, what other calibers you own, etc.

1. 9mm is less expensive. For practice and range ammo (which is realistically over 90% of what you'll be shooting), 9mm is far cheaper. Example: for 500ct at a big retailer like Midwayusa.com, Winchester white box practice ammo is $133.99 for 9mm (115gr), versus $181.99 for .40 (165gr). A difference of $48, so the .40 cost 36% higher. For self-defense ammo, take a popular ammo, such as Corbon JHP. A 20ct box of JHP, in the 115gr 9mm +P is $20.49 at Midway, while the .40 135gr is $25.49. So again, the .40 is $5 (24%) higher cost.

2. 9mm is universally available. Everywhere you go in the world, you will always be able to find 9mm ammo somewhere. The .40 is certainly getting more widespread, and you can get it anywhere in the U.S., but the 9mm is truly universal and there is far more of it out there, meaning it would be more likely to remain available in some kind of crisis situation.

3. The .40 has greater kinetic energy, but they are close.. In a quality defensive loading, a typical .40 round will have about 10% to 16% higher kinetic energy than a 9mm. Take Corbon JHP again, one of the most popular defensive loads. The .40 load with the most energy (135gr) yields 526 ft/lbs, while the highest-energy 9mm is the 115gr, with 466 ft/lbs. So in this case, the .40's energy exceeds the 9mm by about 12%.

4. The .40 is less load-dependent than the 9mm. It is well known that due to its greater size and kinetic energy, the .40 is less load-dependent than the 9mm. There are many subpar and anemic 9mm defensive loads out there that should frankly not even be on the market, as they will not reliably stop anyone. In the case of the .40, the large majority of defensive loads available will meet the "minimum bar" of effective stopping power against a human attacker. With the 9mm, you have to be more selective and do your homework.

5. The performance of QUALITY defensive ammo in .40 and 9mm is very similar. As long as you avoid the lame 9mm loads, and use a QUALITY defensive loading of a comparable type in 9mm and .40 (assuming good shot placement), you will get similar results. Ballistics testing has proven repeatedly that proven defensive loads in both calibers will penetrate ballistic gelatin, auto glass, plywood, clothing layers, and other barriers to equal depths (in some cases the 9mm does even better, due to higher velocity), and will expand to very similar sizes (as Todd notes above). And I have had at two forensic pathologists tell me that when you look at the permanent wound produced by a modern defensive loading, they cannot tell which caliber was used. In fact, a quality 9mm loading will OUTPERFORM a similar .40 loading just as often as the other way around. They are so close, that the demonstrable differences in penetration, expansion, permanent cavity, and proven stopping effectiveness are insignificant.

6. .40 S&W has greater kinetic recoil energy. Obviously, since the .40 fires a larger bullet with greater kinetic energy on the average, due to Newton's 3rd law of motion (for every action, there is an equal and opposite REaction), there will also be greater kinetic RECOIL energy pushing back toward the shooter, compared to a 9mm. And that means the .40 can be more challenging for some people to control. The fact that the .40 has more recoil force is a real, measurable fact. How people respond to that and control it, is subjective and varies by shooter. For some this is no problem. For others, the noticeable difference in recoil and controllability between the 9mm and the .40 is a significant factor in their choice of caliber. Due to health issues (such as arthritis), age, strength, size of hands, or just personal preference, some find that the .40 produces more recoil and "snap" than they are comfortable with, and find that they can shoot the 9mm more comfortably.

Given the above facts, I think either caliber could be a good choice.

Happy deciding!

Larger projectiles, cause more damage. That's observable. Does that make .45 "better" than 9mm or .40? Sure. Does that mean that 9mm as a caliber is weak and ineffective? No. 9mm is a fine caliber for self-defense that will obviously cause slightly less damage than a .45 round because of its smaller size, but it is still capable of penetrating deep enough to reach vitals.

See: http://mp-pistol.com/boards/index.php?showtopic=12949

Do these rounds look radically different?

Handgun_gel_comparison.jpg

I'm no ballistics expert, but I also agonized for a while over which one to carry. I ultimately went with the .40, but I would have been just as happy with the 9mm. I'm not a cop. I've never shot anyone and hope I never do, so I don't have any "real world" advice. But then again, I've found it's best to be aware of those who claim they're authorities based on "real world" experience. The problem is, their one or two or twelve shootings just isn't a big enough sample size to control for all the variables possible in a self-defense scenario. Their experience is invaluable in telling you what to expect as far as fear, perceptions, aftermath, etc. But no one can make sweeping judgments about caliber based on one or two shootings.

If you go with a 9mm, just pay the extra bucks and get the premium self-defense HP rounds. I'm talking the Cor-Bon P+, or Speer Gold Dots, or Hyrdashocks, not that bizarre "extreme shock" fang-face crap.

I looked at page after page of ballistics data and between the top 9mm loads vs. the .40 S&W, there just ain't that much difference. You might - MIGHT - get away with buying cheaper SD loads for the .40, but why take that chance? But when it comes to 9mm, there is definitely a ballistics difference between the cheap stuff and the higher-end ammo. The best I can tell - again, I'm no expert - is that 9mm is slightly more suceptible to under-penetrate in the lighter loadings. But in the hotter loadings, 9mm is very, very close to the .40 S&W or maybe even the .357SIG.

Just remember that S&W doesn't recommend using +P+ loadings in the M&P series. My manual does say that P+ is OK (9mm only; there is no specification for P+ or +P+ loadings in the .40 S&W!).

Intuitively we might all agree that "bigger bullet = better bullet." Certainly, the .45 ACP round has its share of followers! But there's near-universal agreement that the .357 Magnum was (and is) an excellent man-stopper, and yet its bullet was about the same size as a 9mm. My intuition tells me a bigger bullet would be better. But history shows that a relatively small bullet like the .357 can do an excellent job, if the energy and expansion characteristics are corect. Todd G has repeatedly pointed out that, once they expand, the differeing bullet sizes are something on the order of thousandths of an inch. I guess I'd like every extra advantage I can get in a fight, but it's possible to reach a point of diminishing returns. How much extra expense (in money, recoil, wear and tear, etc) is worth getting an extra thousandth of an inch of penetration or expansion?

One other thought to chew on: A lot of folks will tell you that .40 S&W is superior because that's what all the cops are switching to. But remember that cops frequently need to shoot through car bodies. I've seen test data that might indicate that a .40 can do a slightly better job of going through a windshield and still have adequate penetration on the other side (I've also seen conflicting data hinting a 9mm is better, so it's a coin-toss again). But even if the .40 is superior through auto glass, as a private citiizen our types of self-defense scenarios probably won't include shooting through windshields or doors.

It's hard to imagine a SD scenario for an average citizen where barrier penetration is a serious concern. For the most part, if the BG is barricaded, those of us who are not LEO should run away and call 911!

I rambled way too much, but the bottom line is this: Most of us spend way too much time agonizing over the whole 9mm vs .40 debate. I'm no expert, but my research of others' work suggests that if you use a high-quality 9mm load, it just doesn't really matter that much!

Also, it's very important to remember that there is a big difference between +p+ ammo loaded by the Big Three, which is still manufactured to very tight tolerances with pressure data available to gun companies, and +p+ ammo loaded by the smaller boutiques who may or may not even bother to do actual chamber pressure tests on their ammo from lot to lot.

Re: auto glass, having a bonded bullet is much more important than the caliber. A bonded 9mm will outperform a non-bonded .45 as a general rule, and a bonded .45 will out perform a non-bonded 9mm. Speer Gold Dots were the first bonded JHPs in wide use and it's one reason they dominated the LE market for so long. Federal had its "Tactical" line but now there are both bonded and non-bonded bullets marked "Tactical" by Federal, so you have to look specifically for the word bonded. Ditto with Remington (Golden Sabers come in both bonded and non-bonded) and Winchester (Ranger comes both bonded and non).

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Hmmm...lots of common sense is spoken, until they get to the kinetic energy part (a nearly useless measurement, IMO). I think way too much fuss is often made of the kinetic energy factor; after all, kinetic energy is a simple formula which stresses velocity over weight. Therefore, higher velocity rounds like the 9mm are often misrepresented. A more accurate way to see what "hits" the hardest is to observe an IDPA or USPSA match which involves shooting steel targets. Note which ones fly down like they are hit with a rifle, which ones slowly fall over, and which ones sometimes stay upright. Hint: the 9mm isn't the one knocking the plates over like they were hit with a .44 Mag.

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After many decades of taking notes, and spending a ton of money, the Dept' of Treasury, which manages the alphabet teams, has decided that "bullet placement is more important in winning a gunfight than bullet size."

There is no telling how much tax money was spent figuring this out. :taser:

Don't forget, the largest practical defensive sidearm does not have much more kinetic energy than a well thrown major league fastball.

Vital, blood bearing organs must be destroyed, or a nerve trunk must be hit to obtain a reliable stop, and the medulla must be hit for a reliable, IMMEDIATE cessation of hostilities. (precision shots don't happen in a gunfight which will probably occur in the dark, and be OVER in less than 3 seconds!):D

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Something just doesn't look right about this study. I'd have to examine the data on my own. I'm particularly skeptical about the gelatin pics that shows the virtually same mass 357SIG and 9mm JHPs have the same penetration although the 357 has a significantly higher velocity. Maybe they are using very different designs of JHPs? If so, the review becomes apples and oranges.

Having said that, I like both 9mm and 40 S&W. I carry them both, normally not at the same time. I can agree, based on experience, that they both work fine. The 40 has the edge for closer urban carry, but for more distant field use, I prefer the 9mm.

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After many decades of taking notes, and spending a ton of money, the Dept' of Treasury, which manages the alphabet teams, has decided that "bullet placement is more important in winning a gunfight than bullet size.".....

Good point John and I agree with your comments. ;)

I think the best advice ever is to carry the firearm that you can hit with the best - - - quickly!

Another point to make is the round count. I'm often asked why I still carry "only" a 9mm. For one thing its still my "work caliber" and another is the total rounds (stored kills) that I can carry.

Would eight .45 ACP rounds be better than sixteen 9mm? Hard to say, but the worst thing that can happen in a gunfight is to run out of ammo. In a real fight most folks tend to shoot until the threat is gone. We see that in LEO shootings and have always known that in the military (but we're just now training that way).

And finally I have to admit that my selection of more bullets over bigger bullets is indeed driven by my past experience......

The best REAL combat handgun shooter that I ever knew was killed in the middle of a fight with his right hand still holding his slide-locked 1911 and the other with a fresh mag ready to reload. It was clear from the bodies around him that so long as his weapon was running he was winning. I have often wondered if he'd be alive today for the want of a few more bullets over bigger bullets......... :(

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Most data that I have seen indicates that the higher velocity .357sig cartridge actually penetrates slightly less gelatin than 9mm with similar bullet designs, because it expands so violently, but it penetrates hard barriers better because of the velocity.... which is consistent with the superior performance reported by agencies who use .357sig over 9mm or .40s&w.

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Could be Eddie. There is a visible difference in the permanent and temporary wound channel.

I tried to find a comparison on The Box O' Truth but didn't come up with anything. I may look again. That site could some better organization.

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I used to read everything I could in my mid-twenties on ballistics, gel tests, and tried to keep up with all the new calibers and such. Mainly when I was reloading. I was a fact junkie. Now that I am a little older I care less about that stuff. I am still interested in it mind you... but it is more of a passing fascination now.

I think accuracy is the most important thing. Sure it's great to have a larger caliber to sort of compensate for firing under stress. With current bullet designs and top quality handguns being made... it seems that there are plenty of good choices for defensive rounds. As long as you can hit with them.

+1 for "DMark's" comment about capacity.

I loved my .45 and want another, but I would rather have more capacity

for something I am planning to carry. (Just my opinion.)

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Part of why that thread over on the M&P forum fascinated me is that recently I had the same epiphany that many others here have in that it occurred to me that (a.) handguns don't typically offer one-shot-stops, (b.) that shot placement is far more critical than caliber and (c.) the guy who runs out of ammo first is likely to be the loser in a gun fight.

As much as I dearly love my Wilson Combat 1911, eight rounds of ammunition is not enough in my mind. It doesn't matter to me that I am very accurate with it. It doesn't matter to me that I train to aim small and miss small. What matters to me is that eight rounds means I only get to pull that trigger eight times before I have to reload... and that should be while shooting on the move and I'm not that good at shooting on the move yet.

So what gun do I carry more now? My P2000 .40SW because it has 12 rounds capacity. This is also why I am entertaining the idea of a Glock 19 as it adds an additional three rounds of ammo in the exact same size package as my HK P2000 AND I know for a fact that the recoil of a 9mm is negligible enough for me that I can hold it on target and deliver follow up shots with precision and brutality. I'm still working toward that with my P2000 and struggle still with the excessively long trigger reset on it.

SO... this fascinated me because here I am looking at a 9mm for carry and prior to this "enlightenment" I would have more or less looked down on the 9mm as being less than desirable for a self defense cartridge. Now I'm looking at it in a different light.

Enough of my ramblings for now. Just thought it was interesting. ;)

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Dear Mars

The first generation of 357 SIG ammo was loaded with 9X19 bullets. The round exhibited insufficient penetration due to shedding jackets caused by higher velocity. Then, they fixed it.:confused:

The newer generation of 357 SIG ammo has sturdier bullets. They penetrate barriers better. They do about the same tissue damage as the other calibers. What the sturdier bullets do in the 357 SIG is RICOCHET!

The Tenn Dept of Safety conducted testing, and concluded the 357 SIG has a higher potential for ricochet damage than the 5.56 PATROL RIFLE!:koolaid:

The testers recommended the round NOT be used by the state. However, politicians, knowing more than anyone, allowed the round in certain state agencies, and has allowed it for Armed Guard.

The Tn Highway Patrol MIGHT need this round once in a blue moon. They would be better suited with a Patrol Rifle in their cruisers.

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Something just doesn't look right about this study. I'd have to examine the data on my own. I'm particularly skeptical about the gelatin pics that shows the virtually same mass 357SIG and 9mm JHPs have the same penetration although the 357 has a significantly higher velocity. Maybe they are using very different designs of JHPs? If so, the review becomes apples and oranges.

Having said that, I like both 9mm and 40 S&W. I carry them both, normally not at the same time. I can agree, based on experience, that they both work fine. The 40 has the edge for closer urban carry, but for more distant field use, I prefer the 9mm.

All the rounds in that gelatin picture that Doug Carr used were Federal HST's across the board.

BTW the working link to the thread that Tungsten originally posted can be found here, but you have to be a member. http://mp-pistol.com/boards/index.php?showtopic=13933&st=40

Edited by PaiMei
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Guest mikedwood

I like the 9mm mainly due to lower cost equals more practice on the range and usually high capacity in the mags.

If I were going to war I might consider a different choice but for out and about carry when who knows what and probably nothing will happen 9mm is fine with me. Maybe I'll change my mind when I get my permit in and actually do start to carry.

I'm gonna make a guess that I will carry my .38 stubbie the most due to ease of concealment and currently having 4 of 5 different methods of carrying it. If I ever get where I feel out gunned I think I'll... probably freak no matter what gun I'm carrying.

I really believe 9 is fine but more so carry whatever you feel most comfortable with, no matter what it is. .22 or Desert Eagle, or somewhere in between.

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