Shotshell Case

A plastic cylinder with a metal base that contains the shot, wad, powder and primer
Shotgun shooters also refer to a shotshell case as a hull
Hulls have two major parts, the head and the tube
The head is typically made of brass and houses the primer and, sometimes, a base wad
Tubes come in various designs, sizes and lengths and are crimped at the mouth in either 6 or 8 point folds
Hull sizes correspond with shotgun bore sizes, which are based on the gauge unit of measure
The gauge of a shotgun is equal to the number of lead balls (sized the same diameter as the shotgun bore) it would take to weigh one pound. So it would take 20 lead balls the size of a 20 gauge shotgun bore to weigh one pound. (The .410 is the only exception, which is measured in inches)
Shotguns come in the following bore sizes: 10-gauge, 12-gauge, 16-gauge, 20-gauge, 28-gauge and .410

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