Always Match the Data Stamp First
Like rifles, shotguns have a data stamp usually located on the side of the barrel. It indicates the gauge and maximum length of the shotshell that can be fired safely. Gauge and shell length are also shown on the shell base and box.
A magazine 'plug' is inserted in the end of a tubular magazine to limit the number of shells a shotgun may hold. Federal law requires that the shotgun be limited to a capacity of three (3) shells (one in the chamber and two in the magazine) while hunting any type of migratory birds including doves and waterfowl.
Important! Florida hunting regulations state that a shotgun must be limited to holding a maximum of three shells (one in the chamber and two in the magazine) when hunting any migratory game bird. When hunting resident game birds - turkey and quail - you do not have to limit your firearm's magazine capacity.
Understanding a Smoothbore Barrel
A shotgun used for shot features a smoothbore barrel, meaning that there is no rifling. The barrel is thinner than a rifle barrel since it does not have to withstand the increased pressure.