When they say certian bullets are ineffective against carglass....?

Question

What are they saying? I've found air rifles to be effective against car glass, so I'm confused!

Answer 1

What they mean is that certain pistol rounds (like hollowpoints) will go through autoglass but be extrememly compromised and fragmented before they get to the intended target (hopefully a criminal). Controlled expansion hollowpoints ("full metal jacket" hollowpoints) and the old , trusty full metal jacket pistolball rounds penetrate glass easy. It's not whether they break the glass or not, it's how much of the slug is left for it's intended target.

Answer 2

All I can add to the above great answers are that shooting through glass will " deflect " the bullet path. If I remember right, shooting straight into a windshield at face height, the bullet will actually angle down and will not likely hit the intended spot.

Now if you are standing right in front of the car, the angle may be less and will probably hit something but you wont be driving tacks if you're shooting through glass.

Answer 3

During the 1960's it was determined that rounds currently in use by most police departments would not penetrate automobile windshields when fired at an angle. .38 Specials were used by the majority of police departments. KTW ammunition was developed for the specific purpose of developing ammunition that enhanced the effectiveness of police handguns against windshields, car doors, etc. Interestingly enough the bullets used were coated with Teflon to increase the friction between the bullet and the windshield thus increasing its effectiveness in penetrating windshields. Teflon is a component in many cane and crutch tips because it actually increases friction when placed under pressure, even the relative minimal pressure exerted on a cane or crutch tip. Thus the Teflon enhances the penetration of rounds that strike at less than a 90 degree angle of windshields. Windshields are very tough laminated glass that do not shatter like the tempered glass in side and rear windows, so it takes a relatively solid bullet at a relatively steep angle to punch through and effectively find a target.

Answer 4

All good answers. If you are really interested the FBI did extensive testing a few years ago after the big FBI shoot out in Miami in which they lost some good people. Their test included things besides windshields like penetration thru plywood, clothes, etc in an attempt to establish some minimun criteria. If your life depends on it, the choice of bullet is very critical....a bit more so than caliber. I believe the FBI decided they needed about 11 inches of penetration after going thru a barrier as anything less may not reach the vitals/spine of a bad guy for a hoped for instant stop. One or more of those agents were killed by bad guys that had already been hit, hence the testing to try to imporve those odds....and in the end, hence the 40 S&W after they determined the 10 mm to have too much recoil for some...(like it or not), but it still boils down to which bullet one uses in it or any other caliber

Answer 5

Rounds designed for violent expansion, like varmint bullets or safety slugs design to fragment on contact of any thing solid as in, wall, door, car, or even glass like the Glaser.
Will not have the performance that other bullets would have after passing through this obstruction.



D58


Hunting with Rifle, Pistol, Muzzle loader and Bow for over 3 decades.
Reloading Rifle, Pistol and shotgun for over 3 decades.

Answer 6

What do you mean by effective, Jonathan? If you mean that an air rifle will crack auto glass you are correct, but that is not what is meant by ineffective. When you are shooting at a car with a real gun you want to reach the car occupants, not just shatter the glass. Some calibers do this better than others and some bullets perform better than others against barrier such as car glass and sheet metal. Windshields, for example, are built to deflect air. If you are shooting at a car determined to run you over you don't want your bullets to be deflected into the roof liner by the windshield. A truncated shaped bullet will work better against car glass than a round one. A faster moving bullet will also work better than a slower moving one. Hence a .357 Magnum will work better against car glass than a .45 acp.

So you see, it is not just about breaking glass.

Best.

H

Answer 7

Yes, david m is correct! Even impacting car glass can start the expansion of a HP bullet, and possibly derorm it, but they are designed to do that! FMJ bullets will not be effected, but a partially expanded HP bullet will not be as effective!
The glass is destroyed either way, though!

Answer 8

Great answers above :) For better or worse this was one of the reason the military switched to the 9mm. Since most military shootings took place through some obstacle, windshields, car doors, wall board, bulky equipment, etc... they moved to a round with better penetrating ballistics. To bad the .357Sig didn't exist at the time of testing :(

Answer 9

You can't kill a person with an air rifle through car glass. It needs to penetrate the glass and have enough force remaining to kill or incapacitate.
.38 Special rounds hitting a windshied at a certain angle will bounce off and not even break the glass.