There are more varieties of 9mm ammunition than only FMJ and Hollow Point. Most cops now employ hollow tip ammunition because when you shoot someone, the bullet fractures and divides up within them, making it less likely to exit and hurt an innocent bystander. There is also jacketed hollow point ammunition, which is designed for law enforcement officers who may be shot at close range with little or no time to react. FMJ or full metal jacket bullets are the original hollow-point design and still the most popular choice among shooters looking for maximum penetration ability. The term "full metal" refers to the fact that these bullets have a solid core with a hardened layer of steel on either side. They are usually made from 92% copper and 8% zinc materials and are heated and hammered into spheres before being loaded into the gun's chamber. Hollow points were first developed by Remington in 1933. These bullets have a hole drilled through their centers, which allows the gas produced when the bullet strikes something hard (such as bone) to escape. This makes them ideal for animals where you want the animal to feel the impact but not risk being hit by a second shot. They're also good for hunting large game since they can provide deep penetration while minimizing the chance of hitting other things out there waiting to eat your prey. Police departments across the country use hollow point bullets due to their effectiveness at stopping threats.