Ordinary glass shatters when struck by a bullet. Bulletproof glass will withstand one or
more shells depending on the thickness of the glass and the type of bullet. Bulletproof, or bullet-resistant glass, looks the same as ordinary glass. But bullet proof glass is made differently.
The process is known as lamination. A tough transparent layer of polycarbonate plastic is sandwiched between two layers of glass. Brand names of the polycarbonate plastic are Tuffak, Cyrolon, and Lexan.
Bullet proof glass is about 7 to 8 millimeters thick, more than twice as thick as standard window glass. Ordinary single strength untinted window glass is one-eighth inch thick or about 3.2 millimeters.
A bullet shot at bullet-resistant glass with go through the outer layer of glass, but the plastic polycarbonate layer will absorb the bullet’s energy and stop it before it goes through the last layer of glass.
There is some neat physics involved here. It is much like a baseball player catching a hard thrown or hard-hit baseball. To reduce the “hurt”, the player moves his hand backward while catching the ball. The player is allowing the ball to come to a halt over a longer period of time, lessening the force of impact.
It’s the same with the bullet proof glass. The glass, of course, can’t move like the player catching the baseball. But that polycarbonate plastic sheet can dent a bit, stretch a fraction of an inch, and bring the bullet to a halt.
The terms “bulletproof” and “bullet-resistant” glass are used interchangeably. Experts in the field say that there is no such thing as totally bulletproof glass. A very powerful assault rifle round will penetrate most bulletproof glass. A rifle bullet generally has a higher velocity than a handgun bullet and will collide with the glass with much greater force.
The thicker the glass and the more layers it contains, the more protection is provided. The ability to stop higher velocity projectiles increases. High quality bulletproof glass is typically made one inch to two inches thick.
But there are some problems encountered. As the glass become thicker, the weight increases. The cost goes up. Less light gets through, so the interior of a vehicle or building is darker.
In 2007, police stopped rapper Buster Rhymes “for having excessively tinted windows”. Buster’s SUV has bulletproofed glass that was two inches thick.
The President of the United States has at his disposal a dozen specially constructed GM cars called “The Beast”. Those cars do have five-inch-thick bulletproof windows, but also sport an armor-plated fuel tank, an on-board fire suppression system, extra weapons, oxygen supply, blood of the current president’s type, Kevlar reinforced tires, night vision cameras, and secure encrypted communication systems. No, it does not have those James Bond 007 rocket launchers.
Similarly, the current Popemobile carrying Pope Leo VIV is a modified Mercedes Benz and is used for his trips aboard. Bulletproof glass became essential following the May 13, 1981, assassination attempt on Pope John Paul II in St. Peters Square. For the short trips in Vatican City, Pope Francis used a plain Ford Focus from the Vatican motor pool. He loved to drive himself around Vatican City in a 1984 Renault 4 given to him by a priest in northern Italy.








