More important than gauge is what choke do you have and have you patterned it with 0, 00, and 000. My two full choke guns shoot a large doughnut shape pattern at 25 yards and are not good buckshot guns. My IM and IC choked guns shoot the same rounds nice and tight. Your mileage may vary and you can get shells that have a wad that will hold them tight but full and extra full guns as a rule in my experience do not shoot buckshot well.
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