Bullet Weight Question

S

Spencer267

New member
So I'm looking for some real world data. My carry gun is a Glock 19 and I'm probably going to carry Gold Dots. My question is... in the worst case scenario where I might have to shoot through auto glass or even a car door, what would be the best bullet weight for the job and which would have a staighter path after clearing the barrier? Does it even matter with bonded bullets? Again, real world data and even life experience if possible.
 
Spencer267 said:
So I'm looking for some real world data. My carry gun is a Glock 19 and I'm probably going to carry Gold Dots. My question is... in the worst case scenario where I might have to shoot through auto glass or even a car door, what would be the best bullet weight for the job and which would have a staighter path after clearing the barrier? Does it even matter with bonded bullets? Again, real world data and even life experience if possible.
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https://www.youtube.com/watch?v=po0d9grHntM

What I EDC in Glock 43 and HD in Glock 17
 
Spencer267 said:
So I'm looking for some real world data. My carry gun is a Glock 19 and I'm probably going to carry Gold Dots. My question is... in the worst case scenario where I might have to shoot through auto glass or even a car door, what would be the best bullet weight for the job and which would have a staighter path after clearing the barrier? Does weight even matter with a bonded bullet? Again, real world data and even life experience if possible.
Click to expand...
https://www.youtube.com/watch?v=po0d9grHntM
 
The FBI spent a lot of time on this. I haven't seen any of their data, but they determined 147 gr @ about 1000 fps was the best all around choice.

The G9 bullets may be great, but I'm not sold. At least not yet. At any rate the angle of the glass in the above video is no where near what you'd see in the real world. Doesn't prove anything to me until I see the bullets shot at a realistic angle.
 
I will not accept ballistics over reliability but assuming that reliability is not an issue, I lean toward the heaviest projectile that runs well in my gun.

If we are to consider a scenario where a good guy must lawfully defend himself/herself against a badguy in a vehicle, I think angle of impact and the absolute placement of door reinforcements, motors or door mounted air bag systems would probably be more critical than what 9mm ammo you use.

I don't fall into the trap of believing in wonder ammo. Any concern I have over absolute ballistics comes behind reliability and shot placement. If it goes bang and comes out of the barrel at a proper speed, I consider the rest up to me.
 
If we are to consider a scenario where a good guy must lawfully defend himself/herself against a badguy in a vehicle, I think angle of impact and the absolute placement of door reinforcements, motors or door mounted air bag systems would probably be more critical than what 9mm ammo you use.
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A few years ago I did a Bullets and Vehicles course. The above quote is a pretty good summary. All ammunition that was fired through the laminated glass of the windshield was deflected, 9mm, 40SW, and 45ACP. 40SW did seem to deflect a bit less than the 9mm, making me think the heavier projectiles had an advantage there. That said, all of them still would impact the chest of a target even with deflection, but going for headshots might be iffy. We did notice that non-bonded ammunition often had the jacket stripped completely off when passing through the windshield.

As for shooting through the doors, unless you hit a cross piece there was typically less deflection than going through the windshield. If you did hit a cross piece it likely wasn't going through the door anyway. Most rounds fired at the door went straight through it like tissue paper. My main takeaways were that cars really only provide cover that's restricted to certain zones (engine blocks, A, B, and C pillars) and that being in a car is not a place when you want to be when bullets fly. The fact that the car can drive and get out of the place is its greatest attribute.
 
One piece of useful information for a discussion of this is to know the FBI protocols for ammo intended for the FBI's use. Their guidelines are generally accepted for law enforcement use across the country.

http://www.brassfetcher.com/FBI Ammunition Protocol/FBI Ammunition Protocol.html

Rounds built to these standards will penetrate auto glass. In this regard the construction of the bullet is more important than bullet weight. Though that (bullet mass and momentum) is also a factor to consider.

http://www.brassfetcher.com/Handguns/9mm Luger/9mm Luger.html

Here also a lesson on auto glass, doors, etc.

https://www.theboxotruth.com/the-buick-o-truth-3-pistols-and-car-doors/

https://www.theboxotruth.com/the-buick-o-truth-2-windshields-outsidein/

tipoc
 
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Sectional density is a key factor in determining the ability of a projectile to penetrate a barrier.

Momentum is a key factor in determining how much a body in motion deviates from its path when it strikes an object denser than air.

For a projectile of any given caliber, heavier projectiles will have greater sectional density since the cross sectional diameter of the unexpanded projectiles are the same. So 147 grain 9 mm Luger has more SD than 124 grain which has more than 115 grain.

If you look at the muzzle velocities for the various 9 mm Luger Gold Dot loads on the Luckygunner web site, you will find that 147 grain 9 mm GDs have more momentum than 124 grain standard pressure GDs. But the 124 grain +P 9 mm GDs have just a little more momentum than the 147 grain.
 
Sectional density is a key factor in determining the ability of a projectile to penetrate a barrier.

Momentum is a key factor in determining how much a body in motion deviates from its path when it strikes an object denser than air.

For a projectile of any given caliber, heavier projectiles will have greater sectional density since the cross sectional diameter of the unexpanded projectiles are the same. So 147 grain 9 mm Luger has more SD than 124 grain which has more than 115 grain.

If you look at the muzzle velocities for the various 9 mm Luger Gold Dot loads on the Luckygunner web site, you will find that 147 grain 9 mm GDs have more momentum than 124 grain standard pressure GDs. But the 124 grain +P 9 mm GDs have just a little more momentum than the 147 grain.
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Brother... its not rocket science. We all know what a door skin is like and we already know that just about any bullet is going to pass through a standard door skin like butter. It will pass through a door skin in spite of whatever SD= M/A you want to consider. Its more intellectually honest to simply say.. ugh! bullet travel fast, bullet hard, door skin not as hard, bullet pass right through.

What matters is what is immediately behind the door skin ( ie .. electrical components, motors, glass, air bag systems, structural reinforcements, sound dampening media)

Even with all those potential obstacles, most common SD rounds will go right through.

Where high math is going to be involved is discussions involving the degree of windshield deflection vs angle vs mass vs speed. If you want to get all cerebral about something, you can get cerebral about that.
 
in the worst case scenario where I might have to shoot through auto glass or even a car door, what would be the best bullet weight for the job and which would have a staighter path after clearing the barrier?
Click to expand...

I got to thinking about this, and was wondering, if one is not a police officer, why would the need to shoot through a car door even come up?? Shooting through glass I can understand better, but why, other than the satisfaction of knowing what a given round will and won't do, why would you need to shoot through a car door, or other part of the car body?

Cars don't stop instantly if you shoot the driver. And to my way of thinking, it tough to imagine a situation where you were menaced by a car, and had time to (draw?) and shoot the driver, in time to stop the car, AND didn't have time to jump out of the way???

Which brings me to the legal point of justified shooting. If you aren't LEO, how are you justified shooting THROUGH a car door? Even the closed window or windshield? My point is that there could be the argument that there wasn't sufficient threat to justify shooting someone who isn't an immediate threat.


Personally, I wouldn't get too hung up in the small differences in the numbers of momentum or velocity/energy between bullet weights in 9mm Luger. Bullet construction, and especially angle of impact on the hard surface (including glass, which is actually pretty hard, though brittle) matter more than a small difference in momentum.

As far as which will have a straighter path after clearing the barrier? There's no way to know. After breaching a barrier, rounds usually still have a straight path, but it is rarely exactly the same path they had before hitting the barrier. Target medium and angle of impact, plus all the factors in the bullet itself can send that bullet off more than just a little divergent from the point of aim.
 
Laminated glass is hard on bullets. I’d rather be behind a windshield than the “metal” on most vehicles.

Angle of impact is important as well. If a bullet hits an angled surface vs. a 90 degree surface, it will deflect towards the angle the bullet impacts with first (up from inside the vehicle, down from outside).
 
Which brings me to the legal point of justified shooting. If you aren't LEO, how are you justified shooting THROUGH a car door? Even the closed window or windshield? My point is that there could be the argument that there wasn't sufficient threat to justify shooting someone who isn't an immediate threat.
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I bolded the important part above.

Ask yourself why you would need to shoot through anything? I mean any thing to defend yourself or others. It's the same answer. Same question really. Does it matter if it's a car door?

Through a bookcase, through a garbage can, fella shooting from behind a tree, hiding behind a Rhododendron bush, through a refrigerator door, through a window, etc. What you may have to shoot through a thing to stop a threat makes no actual difference. It's what justifies the shooting that is critical and not what you have to shoot through. Same as distance.

If there is not a sufficient threat to justify the shooting then it won't make a difference if you have to shoot through something or not.

tipoc
 
44AMP said:
Which brings me to the legal point of justified shooting. If you aren't LEO, how are you justified shooting THROUGH a car door? Even the closed window or windshield? My point is that there could be the argument that there wasn't sufficient threat to justify shooting someone who isn't an immediate threat.
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Generally, you need to show there is an immediate threat of serious bodily injury using the ability, opportunity, jeapordy standard that is stickied. If the guy in the car has a knife or impact weapon, you are right. If you reasonably believe he has a firearm, his/your car isn’t much of a barrier to him harming you.

Realistically, the best bullet in the best gun with the best shot placement will probably work; but it still might fail all the same. That’s why capacity is important because the more rounds you can put on target the more likely you are to get the statistically likely result.

Edited because bullets go both ways through cars ;)
 
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44 AMP said:
If you aren't LEO, how are you justified shooting THROUGH a car door?
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Best point in this thread!

Easy to forget that folks in the Cop business have different requirements than those of us who just Concealed Carry.
 
Best point in this thread!

Easy to forget that folks in the Cop business have different requirements than those of us who just Concealed Carry.
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Ah not so much actually. A couple of years back there was a fella walking down the street who went up to a fella sitting in his car and started stabbing him through the open window of the car. The fella inside the car would have been entirely justified shooting through the car door to protect himself.

The car door or window makes no difference what-so-ever.

"But how can I justify shooting through a car windshield?" asks the fella. Okay how can you? If the shot will stop an immediate threat to you or others. Same as any shot taken.

tipoc
 
I didn't meant to imply that there were no possible situations where one might need to shoot through a barrier, only that as defensive shooting, I couldn't really think of any.

And I was also mostly influenced by the thought of someone using the car as a weapon, and needing to be shot, because of that. This is a different situation than someone IN the car shooting at you.

However, this does bring up the point, why wouldn't you aim at the person (who is the threat)? Now, I realize that aiming at the visible portion of a person firing from cover could easily result in your shot striking their cover instead of them, and shooting something that will penetrate that cover would be useful, if it happens to hit part of them, but is that the right basis to use as the priority when choosing ammo??

Also, again, I would point out the possible legal issues. We are all waaay to heavily influenced by the thousands of hours of "training videos" ("action movies and TV) we have seen since childhood, and while its natural to think in those terms, its not always legally justified to do what our action heroes do on the screen.

Consider, for a moment, as a private citizen, we don't have the responsibility to STOP the bad guy, we only have the right to defend ourselves from immediate threat. Here's a point to ponder, when the attacker is no longer an immediate threat, you aren't justified in shooting them. This is pretty established. For example, you might be in a High Noon shootout, facing down the attacker and trading shots (actually misses :rolleyes:), but when the bad guy turns away, walks or flees, even if he still has a gun, you're not justified shooting him in the back, if he isn't pointing that gun at you.

SO, consider that no matter what they did the second before, (or what they might do a few seconds from "now") when your attacker is behind cover (not pointing a gun at you that moment, not shooting at you, that moment, maybe you can't even see them) HOW are you, as a civilian, justified in shooting them, through cover? The TV hero is (its in the script), a COP can be, but are you and I going to be justified doing that??

The Jury will decide, I suppose...
 
44Amp, in the civilian scenario I think the question is when the attacker has taken cover, can you then disengage without getting shot? If you are having to run in the hope that he/she won't shoot you in the back or some other, shoot through the barricade and/or advance for a better shot(s). And yes, either way if you live you will probably be going to court.
 
More than a decade ago, ATK conducted a series of Wound Ballistic Workshops hosted by various police departments (and representatives of other police departments also present. The .40 SW was the preferred caliber by police at the time but they tested some 9mm HSTs and Gold Dots against a couple of other competitors.

The tests were done to FBI protocols, including calibrated ballistic gel and the specified manner of testing through auto glass. Two test results of interest to this thread:

ATK Wound Ballistic Workshops

Aurora PD, 6/24/08
From Glock 17, 4.49" barrel
Auto Glass
Speer GDHP +P 124 gr -- penetration 15.25" -- expansion .577 in.

Riverside PD, 7/12/2007
From Glock 26, 4.17" or 3.43"
Auto Glass
Speer GDHP 147 gr -- penetration 8.75" -- expansion .1029"

Note that I am unsure of the Glock 26 barrel length at that time. I am not a Glock guy and when I looked up the Glock 26, I understand the current length is 3.43 inches but some Glock 26s used to be 4.17 inches. Maybe someone more familiar with Glocks can clear this up.

All the results used to be available on the web but have disappeared. I downloaded them a few years back.
 
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