9mm Luger 

The 9mm Luger cartridge is flawed. It has been flawed since its development around 1902 by Georg Luger for his famous Luger pistol. Since then, the 9mm Luger – also known as the 9mm Parabellum, 9X19, 9mm NATO or just the 9mm – has become one of the most popular cartridges on the planet. It is chambered in handguns, submachine guns and rifles, and is the standard NATO round for handguns. Frank Barnes (2006) notes that it is the most widely used cartridge in the United States.

The 9m Luger has become especially popular for small, compact carry guns intended for self-defense. It is a potent cartridge for its size and offers good performance with well-designed bullets.

But the cartridge has a troubling flaw: it’s tapered.