The world's smallest gun is a .22 caliber single shot pistol called the Kolibri, which was designed by Franz Pfannl and manufactured in Austria from 1910 to 1914. It is only 2.5 inches (6.35 cm) long, weighs 2 ounces (56 grams), and fires a 2.7mm Kolibri cartridge that is about the size of a grain of rice. Due to its small size, the Kolibri was not very practical as a self-defense weapon, and only a few hundred were produced.