A shotgun is a larger diameter, smoothbore barrel that shoots a plastic wad capsule with small lead round balls that are called “Shot”. The shot comes in different diameters to use in difference situations. Used mainly for hunting game birds such as pheasant, chuckar, quail, grouse, and also wild rabbits and other small species of edible game.  The shotgun is used also for self-defense in close quarters and sport shooting flying targets . The shotgun is made like a rifle but has a different looking barrel and action. The shells (ammunition) are normally made from a brass alloy or steel head and a strong plastic body. The shell uses a primer as in rifle and handgun to ignite the powder charge which forms a gas and pushes the wad and shot load down the smoothbore at high velocity but lower pressures than the rifle and handgun. The shotgun comes in many variations and what are called Gauges for different uses…the most popular are .410 Ga., 28 Ga., 16 Ga., 20 Ga., & 12 Ga.    There are a few others too but not usually used in hunting, defense, or sport shooting. The shotgun comes in single-shot, double barrel (in both side by side barrels or over/under barrels), single barrel pump type for repeat firing and semi-automatic.