9mm versus 40

[Seraphim]

There is no such thing as knockdown power or stopping power - a bullet has neither mass enough or energy enough to do either. There is accurate shot placement. There are numerous factors about how a round will react - and the reactions it will cause - when entering its target. I had photos of a man with 32 9mm rounds in his chest and abdomen. He didn't stop until one round severed the right connection. Neither the 9mm nor the 40 cal is superior as long as you can hit your target properly. If you can't, the caliber and type of round doesn't matter anyway. Choose one and become an excellent marksman.

 

[misplacetexan]

I bought the Shield 40, because my duty weapon is a H&K P2000 40cal. Easier and safer to just have 40 cal ammo in the house. Can't make a mistake and grab the wrong ammo in the heat of the moment.

 

[Arik]

I said this in the other thread.

Everyone, and I mean literally everyone, shoots better with the 9mm than the 40 of the same gun. It's that simple.

You can enjoy shooting whatever you want, you can carry whatever you want, you can enjoy/like/prefer anything, but be honest about your priorities. For some people, being able to say "I shoot the 40 cal" while believing the 9mm is ineffective is more important to them than what they would shoot better. If optimizing your performance in life or death situations is not a priority, that's completely your prerogative. Saying you like/prefer the 40 is a mutually exclusive statement to saying you like/prefer shooting your best. My problem with it comes in when such people try to convince others they need the 40.

Depends on the gun. I shoot my Glock 19 and 17 better than I do my Glock 22 but I shoot my HK P2000 40s&w between than the Glock 19/17.

I have no emotional attachment to any gun or caliber so long as they are proven and relatively inexpensive to practice with. I have a 40 because at the time it was the most abundant choice of ammo. I like it, it does what it was designed to do ....if there was no 40 id be just as happy with a 9 end of story.

 

[McE]

After saying "the same gun", "depends on the gun" is kind of missing the point.
You shoot a 17 better than a 22. That's relevant. You may shoot a different model 40 better than the 17, just as I shoot my M&P45 better than my Kahr PM9, which of course is hardly only due to caliber.

I've personally run identical P2000's, V3's, 9mm and 40, on the clock. I'm faster with the 9mm. A part of being faster is a faster target reacquisition, which is synonymous with being more accurate over the time period.
I, too, also shoot the P2000 better than the Glocks, but when you compare different guns like that, you've got so many other factors- grip angle familiarity, sight outline style, trigger feel, ergonomics, etc.

Btw, if you haven't already, throw an HK45c mag release on that P2000 of yours. Makes a world of difference. Saved me a few seconds from faster reloads over the tiny original release.

 

[JMichaelTX]

There is no such thing as knockdown power or stopping power.

Really? You know this for a fact? There is no weapon which can completely knockdown a person, stop them in their tracks?

Are you an engineer or scientist? Have you done the calculations, the simulations? You present nothing but assertions.

What about shotguns? Bazookas? Machine guns?

You have made a very broad and sweeping statement, which I believe has no basis in fact.

 

[McE]

Really? You know this for a fact? There is no weapon which can completely knockdown a person, stop them in their tracks?

Are you an engineer or scientist? Have you done the calculations, the simulations? You present nothing but assertions.

What about shotguns? Bazookas? Machine guns?

You have made a very broad and sweeping statement, which I believe has no basis in fact.

You don't have to be an engineer or scientist to know there's no such thing as the term people throw around of 'knockdown power'. This doesn't mean there aren't things that can knock a person down or disperse them into meaty chunks.

But you won't find any handgun bullets that will knock a person off their feet and on their *** as if you were throwing a baseball to knockdown a milk bottle. A person may crumple, keel over, jump like a scared cat, do a jig, or any number of reactions that are not a direct transferring of force in the same vector as the bullet. Knocking a person down is a function of physiologically causing them to crumple by disrupting the central nervous system, or psychologically removing their will to stand. I guess if you shot out their kneecaps all gangster-like then they would be knocked down as well. It's not an effect like getting tackled by a football player.

"Stopping power" is less of a bunk buzzword. That usually refers to cumulative statistical data from actual shootings where caliber and incapacitation was noted. Still pretty loosey goosey since there are a ton of factors not recorded like distance, location of shot, type of bullet, what internal structures were disrupted, etc. So there is such a thing as a roughly assembled "stopping power" ranking based on the collected info from which calibers used produced incapacitation more often in shootings than others.

 

[V0OBWxZS16]

Really? You know this for a fact? There is no weapon which can completely knockdown a person, stop them in their tracks?
...

In terms of literally knocking a person down no reasonable firearm is capable of doing so. The explanation is very simple. You remember "equal and opposite" right? Anything that can knock down the shootee will knock down the shooter. This is exacerbated by the shooter also having to deal with the momentum of the high-speed gasses exiting the muzzle in addition to the momentum of the projectile while the shootee only has to deal with the momentum of the projectile.

 

[Rustyt1953]

Really? You know this for a fact? There is no weapon which can completely knockdown a person, stop them in their tracks?

Are you an engineer or scientist? Have you done the calculations, the simulations? You present nothing but assertions.

What about shotguns? Bazookas? Machine guns?

You have made a very broad and sweeping statement, which I believe has no basis in fact.

Now that's the way to warm up to folks.

Use the search function. This subject has been beaten into submission.

If you want "knockdown" power, I would suggest a wrecking ball.

 

[JMichaelTX]

You don't have to be an engineer or scientist to know there's no such thing as the term people throw around of 'knockdown power'..

Actually you do need to know how to properly use the scientific method to investigate the power of any system. Most people don't know how to do this as evidenced by the many faulty "tests" of 9mm vs 40 cal on YouTube.

What I object to is the use of a categorical broad statement like "There is no such thing as knockdown power or stopping power."

I am not saying that use of any weapon will guarantee the person will be stopped. However, there are sound physics that indicate some weapons are more likely to stop a person than others. A 12 gauge shotgun is more likely to stop a person than a 22 pistol, for example.

 

[McE]

It wasn't necessarily as broad a statement as you're taking it to be. You're reading it literally and out of context. We're talking about handgun rounds, specifically 9mm and 40. In that context, 'there is no such thing as knockdown power' is correct, because you can't use 'knockdown power' as a criteria to compare the rounds in question. You may as well try to compare which round is better based on the criteria of how many unicorns they have harvested. You're ignoring your own context by bringing in bazookas and machine guns. You're getting emotional yourself even though you address emotionality from the start.
It's also a commentary on the rampant use of the term by the less informed. Someone who talks about handgun ammo and 'knockdown power' is very highly likely to only be informed by poor sources. It's the same feeling aroused when someone declares G2 RIP ammo as the best choice for carry ammo because they were informed by marketing materials.

 

[V0OBWxZS16]

Do you really trust the government?

"The government" is not a homogeneous entity. Units within a particular branch are not homogeneous either. The firearms training and ballistic experts at the FBI do not deserve this level of distrust. This apparently leads to the next error:

Presumably, these studies were either made by, or authorized by, the FBI. So, if they lied/misled in the past, why should we trust the current report?

They are referring to "studies" performed by other people and entities.

In paragraph #1, it seems clear that the FBI needs to identify which ammo likely leads to failure, and which ammo likely leads to success. Whether it be 9mm or 40cal, we need to know this!!

The FBI testing standards are well known. You can find out for yourself!

#4: Clearly the FBI and LEO's need much better training so that they can improve on their 30% hit success.

A big problem is that bad guys tend to move or hide during gunfights. I propose that we train criminals to stand still and in the open. That would save lots of money on LEO training.

#9: In spite of the FBI recommendation, there is no evidence that 9mm provides any improvement over larger rounds (.40, .45).

"the majority of the study participants have shot more quickly and more accurately with 9mm caliber Glock pistols."
+
"an operating room surgeon or Medical Examiner cannot distinguish the difference between wounds caused by .35 to .45 caliber projectiles."
=
9mm is an improvement over the larger rounds.

Seems like the FBI has a lot of work to do to improve their own firefight efficiency/success, as well as LEOs in general.

Switching to 9mm is an important part of that work

 

[Arik]

After saying "the same gun", "depends on the gun" is kind of missing the point.
You shoot a 17 better than a 22. That's relevant. You may shoot a different model 40 better than the 17, just as I shoot my M&P45 better than my Kahr PM9, which of course is hardly only due to caliber.

I've personally run identical P2000's, V3's, 9mm and 40, on the clock. I'm faster with the 9mm. A part of being faster is a faster target reacquisition, which is synonymous with being more accurate over the time period.
I, too, also shoot the P2000 better than the Glocks, but when you compare different guns like that, you've got so many other factors- grip angle familiarity, sight outline style, trigger feel, ergonomics, etc.

Btw, if you haven't already, throw an HK45c mag release on that P2000 of yours. Makes a world of difference. Saved me a few seconds from faster reloads over the tiny original release.

I would like to compare a P2000 9 and 40 but I never see any 9 for sale. The one time I did, about a year ago, I had funds tied up in something else

Reason I mentioned those two is because I actually shoot more Glock. It's what I carry and have been shooting longer than any other type of gun. The trigger is very familiar I just pick up any model and it's the same as my carry. The hammer fired P2000 takes me s little bit to warm up on....a few mags worth to remember the trigger, the pull and where it breaks. But once I get the rithem down it goes pretty quick

I have not and never thought of that. Thanks I'll check it out. Why the 45c? Is there a difference between the C and FS?

 

[hardluk1]

A lite handgun 3.5" and under I rather have a 9mm .

Once the barrel hits that 4" range and weight is increased to 22oz + I rather have 40sw . Loads can be as soft shooting as a 9mm with close to the same energy levels or hot enough to hit 600ft lbs from a 4" barrel .

You shoot what you can control well .

 

[10mmauto]

You bought the gun, now you're doing the research?

Lesson learned.

 

[JMichaelTX]

You bought the gun, now you're doing the research?
Lesson learned.

Let met start by saying it is generally well known that we learn more from our mistakes than from our successes. However, the ego of many people don't allow them to acknowledge their mistakes, and so don't learn from them. I am not like that. If I am presented with new, credible, information, I will definitely consider a change in my position. As I stated in my OP, AFTER I had purchased the Shield 40 I came across new information that suggested that perhaps 9mm is a better choice. That is why I posted this thread.

Actually I did considerable research *before* buying the Shield 40. From that research, I saw no compelling reason to select the 9mm version. I talked to a number of people who thought the 40 caliber was better, and I found a number of blogs/articles/videos which either found the 40 caliber a good choice, or a better choice. I did not find any credible sources arguing against the 40 caliber on a performance basis. I did note that the practice rounds (FMJ) for a 40 were generally more expensive than a 9mm. Since the 40 caliber does provide more energy, more impact, it seemed logical to select the Shield 40.

So far in this thread, no one has presented any data that supports the conclusion that using a 9mm is *materially* more effective than a 40 caliber. I have seen a lot of assertions, but no data, and most of the time not even a link that supports the assertion.

So, as I said in my OP:

So, if the data conclusively points to the 9mm being materially better at knockdown or stopping power, then I will consider switching to a Shield 9mm.

Some of you may choose to quibble with my use of the terms "knockdown" and "stopping power", but let me ask you this: When you are faced with a threat, isn't that exactly what you want to do, to stop the threat?

 

[Llando88]

Bill Wilson recently polled 15 experts in the field on caliber in another forum.

https://pistol-forum.com/showthread.php?17082-Caliber-the-experts-choice-FYI

The vast majority (13 of 15) use 9mm.

Doc Roberts himself said, in that very thread:

"Current 9 mm is the best choice for the vast majority of defensive uses--it is what I carry; the only exception might be in jurisdictions that have an illogical magazine capacity limit of 10 rounds or less, then some consideration might be given to going with .45 Auto. Also, if in a predominately wilderness area, .40 might be a reasonable option, although on my recent 100 mile backpacking trek through the Sierra's, I just stuck with 9 mm."

LEOs and recreational shooters are turning away from 40: M&Ps and other brands in 40 litter the shelves of my LGS.

Police Departments and self defense shooters across the country are choosing 9mm, for the reasons stated: across the spectrum of users, 9mm offers better shot placement, faster follow up shots, increased capacity, reduced pistol maintenance, and lower training cost.

And since the penetration / wound cavity studies support the conclusion that both rounds in JHP are essentially equally effective in lethality, what's not to like?

That being said though, if *you* enjoy your Shield 40, and you shoot it well, then go ahead and shoot it.

That's what matters.

Peace out, as they say.

Rich

 

[JMichaelTX]

Thanks, Llando88 (Rich), for your balanced post that included links to references.

Here is a related thread that some may find interesting:
Is the .40 dead?

 

[Llando88]

Thanks, Llando88 (Rich), for your balanced post that included links to references.

Here is a related thread that some may find interesting:
Is the .40 dead?

No worries.

Good luck with the Shield 40. It is an excellent compact CCW, reliable and accurate. The 40 S&W will get the job done.

Question for you: Do you enjoy shooting it?

 

[JMichaelTX]

No worries.

Good luck with the Shield 40. It is an excellent compact CCW, reliable and accurate. The 40 S&W will get the job done.

Question for you: Do you enjoy shooting it?

Yes, I enjoy the Shield 40 very much, and I have no issues with recoil nor rapid-fire, as some report. I scored 241/250 in the Texas Concealed Handgun License class, and that included several 5-shot rapid-fire rounds.

 

[Llando88]

Yes, I enjoy the Shield 40 very much, and I have no issues with recoil nor rapid-fire, as some report. I scored 241/250 in the Texas Concealed Handgun License class, and that included several 5-shot rapid-fire rounds.

Outstanding! It is a good little gun, by all accounts. For you, sounds like a winner.