police switched to the ..... because the old ..... would not consistently penetrate a windshield.
This is a combination of urban legend and actual valid complaint, and NOT a new thing at all.
It is a matter of cartridge load, and impact material and angle. When the era of "auto bandits" arrived, many police turned to the .38 Super, because the .45 and .38 Special were simply not good enough penetrating car bodies. (I never heard of the 9mm Luger ever being considered
)
When the .357 Magnum arrived, it became the king for that. The famous "crack an engine block" performance comes from that era.
Car bodies had actual steel in them in those days, and windshield glass was ordinary glass, and nearly always vertical or close to it.
I saw a write up once (in the 70-s) using 50s-60s cars for tests, and one of the things discovered was that the standard 200gr .38 Spl would not reliably penetrate a car windshield, when fired from a snub nose (Det Spl) but would get through, fired from the standard 6" service revolver.
Today, windshields are made of composite layers (safety glass), and are very often sloped at very good angles for ballistic protection. (think of the front slope of a tank's armor).
It is the combination of hard surface, and angle that defeats the bullet. Even rifle rounds "glance off" certain angles (and curves) when a 90 degree shot will punch through easily.
Elephant hunters learned in the heyday of the ivory trade that there is a certain velocity range/bullet weight needed to get through the elephant's skull. Rounds below that range wouldn't get in and do the job, and rounds above that range (higher velocity) would glance off, too often for comfort.
It also works that way for other things. right size & speed (for the material & angle) it gets through. Outside of that, either way, usually doesn't.
To penetrate a car, bust the engine, kill it, probably the best handgun rounds for that were made by KTW. Needle pointed tungsten carbide, Teflon coated.
These were the rounds that (after a decade or two in production) when discovered by the anti-gun zealots, created the "Teflon coated Cop Killer Bullet" scare. They were Teflon coated, all right, not for penetration (although I don't think that hurt any) but to protect the bore of the gun they were fired from. Made for, and only sold to the police market.
NEVER sold to the public. Never saw or heard any data about them ever being used to shoot any police, anywhere. Only in the minds of the antis, and in Hollywood movies financed by them.
