A shotgun shell is a type of ammunition designed for use in a shotgun. It typically consists of a cylindrical casing filled with gunpowder and projectiles, known as shot, which can be small pellets or a single slug. When fired, the gunpowder ignites, propelling the shot out of the barrel in a spread pattern, making it effective for hunting birds and small game. Shotgun shells come in various gauges, which indicate the size of the shell and the shotgun it is compatible with. Common gauges include 12, 20, and .410. The shells can also be loaded with different types of shot, such as lead or steel, depending on the intended use and local regulations.