Is 9mm enough to shoot through a car door or window/windshield?

That's correct. However, a simple lack of evidence is not the same thing as a lack of evidence that persists after a concerted, prolonged and properly focused effort to find that evidence.

At some point, after decades of well-funded organizations and gifted people trying very hard to come up with proof and failing, it begins to makes more sense to work from the starting assumption that there's no proof than that there is.
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Sometimes we can look in the wrong place for what we want to know.

What are we looking for proof of? (Or what is being asked for when they ask for "proof" in this case.) It's proof that one service caliber round may be more effective at stopping attackers then another. Lab proof. Proof that we can replicate. This is what Marshal and Sanow tried 20 years ago but lost their way on and went down a rabbit hole of One Shot Stop theory. Proof of that type will be impossible to obtain. One way or the other it can't prove anything one way or the other. It can't prove the 9mm is as effective than another round or prove it's less effective. Too many variables and too little verifiable evidence. But it's the wrong questions and an irrelevant one.

When some one says it's not proven that one service round has more effective terminal performance than another what they are saying is irrelevant to the discussion. Because that proof can't be found one way or the other. So we have to answer a different way, because the answer is there.

What makes one round more powerful than another and what evidence do we have of that? We know the answers to those questions.

Is a well placed shot better with a 9mm than a miss with a 10mm? We know the answer to that.

What bullet will do more damage to tissue and potentially make a more devastating injury, the 9mm or the 10mm? We know the answer to that.

Should we match the tool to the job? We know the answer to that.

Always choose the most powerful round that you can handle well from the gun you've chosen for a particular job. This is a simple way of approaching it and relies on the intelligence of the shooter.

We know that the .357 mag is a more powerful round than the 38 Spl. We know it can be carried in a wheel gun as small as a K frame S&W. We know we don't want to put a hunting round in it if our goal is self defense. We also know that it can be more effective as a self defense round than the 38 Spl. That's proven.

Sometimes it's better to carry a J frame snubby well concealed. Some times a 4" barreled 686 on the hip. Match the gun to the job.

We also know that many people can't shoot a 5 shot J frame loaded with .357 well enough to be sure of it for self defense. In that gun with our theoritical shooter, 38 Spl. will be a better choice for most, if the situation they are anticipating calls for that back up gun.

tipoc
 
It can't prove the 9mm is as effective than another round or prove it's less effective.
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Of course it can. It's easy to show that one round is more effective than another if you allow a wide enough variation in the performance parameters.

The problem is that for years, many have assumed that because a round with quadruple the kinetic energy of another round outperforms it in a practically significant way that the same principle applies when comparing rounds that have much more similar kinetic energy levels.

It's not that it's impossible, or even all that difficult, to show that one round outperforms another in a practically significant manner. The difficulty comes when one takes a number of calibers in the same performance class and tries to compare them.
When some one says it's not proven that one service round has more effective terminal performance than another what they are saying is irrelevant to the discussion.
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Proof of practically significant differences in real-world performance is all that's relevant when talking about "more effective terminal performance" because they're synonymous.

What does it matter if one round expands a tenth of an inch more than another if it can't be shown that the attacker stops faster as a result?

What difference does it make if one round has more ft.lbs. of energy if it can't be shown that it takes fewer shots to stop an attacker when using it?

Who really cares if one round has a higher power factor or goes a half an inch deeper into ballistics gel if there's no proof that it fails to stop attackers less often?

What's the value added if one round destroys an additional ounce of human tissue if even the experts don't agree that it provides a significant advantage to the person who chooses it over another?

None of it matters if it can't be expected to influence the outcome in a practically significant way. So then, why do people measure those things if no one has proved that the range of differences across the service pistol caliber class makes a practically significant difference in the outcome of gunfights?

Because they're easy to measure. So because they are easy to measure they are frequently measured and reported. As a result, many people have come to assume that they must also be important. In fact no one has shown that the variations we see in these parameters across the service pistol calibers makes any difference in the outcome of real world defensive scenarios.

It comes down to this. Let's say a salesman offers two options with different costs and tells the customer that the more expensive option is better but that although many people and organizations have tried for years no one has ever been able to prove it. What makes more sense, to buy the expensive option without proof that you're getting anything extra for the extra money or to buy the more economical option that no one can prove is inferior?

I guess some people find a lot of confidence in carrying a particular caliber and if that's really important to them and they're not significantly handicapping themselves by their choice then more power to them.

Otherwise it comes down to how much you're willing to trade for something that no one can prove actually provides any practical benefit.
 
.44 magnum is a good choice

A 357 is a good weapon, but I've seen.38s careen off windshields No good in a city like this ...

Dirty Harry :)
 
Sometimes things can be understood without proof being provided.
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In simple cases that is often true. Unfortunately intuition becomes less useful--frequently even misleading--when the situation is not simple.

This comment actually provides important insight into why this debate is so persistent and why the two sides often talk past each other. That is common in situations where one or both sides of a debate are operating from the standpoint of belief without proof.
 
Who is going to be shooting through a windshield or a car door in a true civilian self defense situation? That sounds "offensive" to me, but I will go ahead and put my flamesuit...
 
My interest is not in shooting through vehicle windshields or doors. I'm more interested in the ability to penetrate heavy bones, muscle, tissues, deeply, without deflecting, in a potentially large, very heavily built adversary.

We can never know what a potential adversary may be like, but it is not the least bit unlikely that such a threat may be very large, very heavily built, muscled, hopped-up, or on alcohol. Chances are quite remote that I would ever need to defend against such a person, but I arm myself more for possibilities, not certainties.

My preference for heavier bullet weight afforded by larger caliber is largely informed by testimony put forth by industry analysts such as Fackler, Doc Roberts, and others who have direct experience that has demonstrated to them a greater ability, generally speaking, of heavier bullets to crush through bone with less likelihood of deflecting. Anecdotal accounts from hunters, as well, of heavier calibers having greater penetrating effect on animals such as dogs, wolves, coyotes, and deer also contribute to my particular reliance on 180 gr .40 cal bullets rather than smaller caliber, lighter bullet options. Further, it simply stands to reason that among the service calibers, heavier bullets of larger caliber would be more likely to crush and then penetrate through bones and such, with less likelihood of deflecting, than lighter bullets of smaller caliber.

In a defensive situation, one may be fortunate to face a slightly-built Mama's-boy threat who is standing arms by their side, straight face-on to you, soft belly just waiting to accept bullets. But more likely, the adversary will have arms outstretched in front of himself, possibly turned somewhat one way or the other, possibly someone heavily-built from many years of working out in the prison weight room... you just don't know!

If larger calibers and heavier bullet weights didn't offer increased ballistic effect over smaller calibers and lighter bullet weight, they wouldn't have been developed, wouldn't exist, and no one would shoot them. If 9mm was the "magic bullet" caliber, the other calibers would all be gone in short order.

No caliber is the magic bullet caliber. And, of course there are differences gained, even with incremental changes in bullet diameter, bullet weight, and bullet design!

NONE of this constitutes "proof" to me that my choice is likely to have greater ballistic impact in a given situation, but it's more than enough for me to have an understanding that the heavier bullet of larger bore is likely to serve me at least marginally better than a lighter bullet of smaller caliber, possibly significantly better. And since I have found platforms and load choice combinations that are easy and very controllable for me, while also having high capacity, my choice is a "no brainer" to me. I'm confident with it.

Not that it is the only choice that would serve me.

Not that a lighter weight 9mm bullet couldn't be effective.

But that it is an excellent choice which combines the most important elements in my estimation.

That choice would be M&P40 or SIG P320 40 with 16- and 15- rounds of 180 gr Federal HST.

Other choices can serve well, some being .45auto, some being .357SIG, some being 10mm, some being 9mm. But my preferred choice provides a blending of caliber, bullet weight, terminal performance, high capacity, and ease-of-shooting well that is simply ideal for my needs. I understand this without requiring any particular kind of "proof".

Choose your weapons, gentlemen. And may good luck be on your side.
 
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Windshields are constructed of 2 layers of glass with plastic sandwiched between them. Shooting through a large truck windshield that is near vertical is no problem. Most cars and trucks today have them at a severe angle, making it harder to penetrate. Side window glass is all tempered glass that crumbles into bits when hit with a rock. No barrier to bullets at all. Neither is the flimsy sheetmetal and cheap plastic that most cars are built from. My $0.02.
 
Who is going to be shooting through a windshield or a car door in a true civilian self defense situation? That sounds "offensive" to me, but I will go ahead and put my flamesuit...
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I don't plan on ever shooting. I feel I am more in my comfort zone as a witness or screaming like a little girl while I "brave Sir Robin" my happy arse away.

That being said there have been several instances over the last few years of people using vehicles as there weapon of choice or at least initial weapon.

I don't think it is a pure flight of fantasy to envision a legal use of force where a civilian may have to shoot through auto glass.
 
Personally, I don't see how I am better off in front of a car coming at me with a dead driver than I am in front of a car coming at me with a live driver. I'm using that time to get my elderly overweight arse out of the way of the car. I thus don't consider windshield penetration in ammo selection. Interesting to me that so many do. I just wouldn't consider a handgun as a good means of reducing that particular type of threat.
 
My guess is shooting through the glass from the inside is more likely than shooting in, and a side window more likely than a windshield. I don't spend any energy worrying about it though.

CSlinger a great Monty Python reference! Thanks for the chuckle.
 
Glenn wrote:
I took a class on such. It was not difficult to shoot through windshields, side windows or doors with quality modern 9mm. For example, the Hornady Critical Duty rounds and similar.

The only funny thing we saw that was a 12 gauge slug didn't make it through the door as it hit some side beam and was deflected down. A rare anomaly.

You'd be better off training to do such than thinking a 40 or 45 is a wonder bullet compared to a modern 9mm. AAR on such:

https://pistol-forum.com/showthread....ight=spaulding
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But training cost time and money and might challenge some of my dearly held notions about firearms and self defense. :eek:

I enjoyed the AAR.
 
Is 9mm enough to shoot through a car door or window/windshield?
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Even the lowly .25ACP will pass through today's car doors with little loss of speed. I'd imagine that most any handgun caliber could do that.
 
To partially address the OPs question:

During a recent in-service training the firearms instructors put on a little demonstration. They removed the car door of a mid-size sedan keeping its interior upholstery and internals intact with window rolled up. They then placed a sheet of plywood behind the door.

They took a Kel Tec P32 loaded with 5 rds of .32 ACP and fired all 5 rds into the side of the door standing about 10' away. Of the 5 rds fired, all 5 penetrated the outer skin of the door. 3 of the 5 rds penetrated the outer skin and entered through the door completely striking the plywood - 1 bounced off the plywood, 2 just barely entered the plywood.

Moral of the story: don't use your car door as a barricade for cover if you can avoid it.

Albeit, not scientific. But quite compelling.
 
The Hornady Critical Duty met all 12 requirements of the CIA (Critical Defense met only 8 of 12). It's made to go through glass, fabric and bone before it opens. I have it in 9mm and .45ACP.
 
armedleo said:
They took a Kel Tec P32 loaded with 5 rds of .32 ACP and fired all 5 rds into the side of the door standing about 10' away. Of the 5 rds fired, all 5 penetrated the outer skin of the door. 3 of the 5 rds penetrated the outer skin and entered through the door completely striking the plywood - 1 bounced off the plywood, 2 just barely entered the plywood.

Moral of the story: don't use your car door as a barricade for cover if you can avoid it.
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Sounds like to me that the door provided pretty good cover from the .32's. Much better than nothing.

Try shooting a piece of plywood from 10' with a P32 without a door in between and see what happens.

It's been awhile, but I seem to remember mine pretty easily going all the way through 2x4's at 3 times that distance.
 
I'll note the FBI uses a specific ammunition. The 147-grain Speer Gold Dot G2. So I'd conclude that specific load in 9mm is a "yes".
 
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