Basic Shotgun Characteristics
A shotgun shell contains 1 to 1 1/2 oz of metal pellets. The size of the pellets is indicated by a number. Size 2 pellets are called #2, with #4 pellets being somewhat smaller, and #6 being smaller again. Note: There are 2 common numbering systems for shotgun pellets; Australian/British and U.S.. We will use the former throughout these web pages.
When the shotgun is fired the pellets emerge in a cluster and spread out as they travel through the air.
Imagine a large sheet of cardboard placed 40 yards from the gun. It will be peppered with holes when the cluster of pellets hits it. Now imagine a reference circle of diameter 30" drawn on the card and a shot aimed at the center of the circle. Some of the pellets will land in the circle and some outside it. We will say that a shotgun has a 70% choke if 70% of the pellets fall inside the reference circle at a range of 40 yards.
Sample Shotgun pellet pattern
The percentage of pellets in the reference circle is determined by the shape of the barrel of the shotgun with many barrels having a slight narrowing at the end to squash the pellets into a tighter pattern. Some shotguns even have a "screw in" constriction so that the choke can easily be altered.
Note that a shotgun with a 70% choke using one type of shotshell won't necessarily have a 70% choke when using a different type of shotshell.
When the shotgun is fired at a duck, the duck is either bagged (hit and retrieved), wounded (hit and not retrieved), or missed. It is customary to call a duck a cripple if it is ``downed'' but not retrieved by the original shooter. Cripples are thus a subgroup of wounded birds.