Bullet-proof vest

A bullet-proof vest (also called body armor) is an article of protective clothing that works as a form of armour to minimize injury from being hit by a fired bullet. They are comonly worn by police forces and the military.

The above name is a misnomer as any sufficiently powerful ammunition can penetrate such a vest. However, it can be valuable protection against common small arms ammunition. Vests may be augmented with metal or ceramic plates that provide extra protection to vital areas. Some vests are also designed to protect against knife attacks.

Also contrary to the public image, a vest does not protect the wearer by deflecting a bullet, but rather the vest's material, usually Kevlar, works by presenting a series of material layers which catch the bullet and spread its momentum, hopefully bringing the round to a stop before it can penetrate into the body.

People who wear this kind of vest also have to remember that while it can prevent a bullet from penetrating, they can still be affected by the kinetic energy of the bullet which can produce serious internal injuries.

The oldest bullet-proof fabric was made from silk. This was cabable of stopping some slow rounds from black powder guns. A more modern "flak jacket" was developed in World War II from nylon fabric but was only capable of stopping flak and shrapnel, not bullets. Modern bullet-proof vests made from Kevlar were tested by United States police forces in 1975. Since then several new fibers for bullet-roof fabric have been developed besides Kevlar.

See also physics of firearms, ballistics