The Origin of Guns

It all started in China, where gunpowder was first created. In the ninth century, alchemists blended charcoal, saltpeter and sulfur into a powder called huo yao, which was used to treat skin infections. Armies quickly learned the powder could be used in bombs, mines and other weapons. Gunpowder was transported to Europe in the 13th century, likely over the Silk Road trade routes through central Asia. Rival nations refined gunpowder recipes in the ensuing centuries before arriving at the optimum mixture: approximately 75 percent saltpeter, 15 percent charcoal and 10 percent sulfur. These early guns were nothing more than large caliber cylinders of wrought iron or cast bronze, closed at one end and loaded by placing gunpowder and projectile in the muzzle, or open end.

Nowadays firearms are a little more sophisticated.

Some Early Guns
Some Early Guns