Cartridges containing bullets are the most common type of shotgun ammo. The projectiles are tiny spheres made of various metals, including lead, steel, bismuth, tin and zinc.
Each metal behaves differently. Lead has some properties that make it one of the most effective materials for tournament shooting. It is relatively heavy and therefore keeps well its explosive force. Also in a soft form, but modifies it leaves the barrel. This causes the pattern of shot is more expanded than the use of other materials, still delivers a large amount of energy. There is some evidence that because steel pellets do not deform, they maintain their round shape throughout their journey, they hurt animals without killing them more often than lead.
Until the early 90s, most of the projectiles was lead. Environmentalists studied its effect on the ecosphere discovered the remains of lead bullets left in the rivers and forests had harmful effects on wildlife and endangered contamination of drinking water. Lead shot has been banned from waterfowl hunting in the United States since 1992, and various types of steel and alloy now used instead.
The rule of thumb for the size of the projectile is the higher the number, the smaller the diameter. There is a consistent pattern in the United States, but worldwide the numbers do not correspond to any specific measurement of the table. In Chuck Hawks' Shot Pellet Information and Recommendations (English) framework of information for ammunition, you will find a guide to the various sizes in the United States and for which they are intended. In hunting, a smaller ammunition is used for a tournament of smaller and larger for a larger tournament. buckshot ammunition type is a large caliber projectile that got its name for being used for deer hunting. As different materials have different weights and characteristics, the size of the projectile itself does not say much. For example, if you're shooting with steel, you should use larger shot than when using lead in their hunt.