1 in the barrel and 2 in the mag.
You have to have a solid plug in the tube that does not allow the tube to hold more than 2 shells.
The plug can be the plastic one you can buy for your model or a piece of dowel rod.
There has to be something in the tube that cannot be removed with out disassembling the gun.
A guy at Ridgefield got cited for having a removable object. Don't know what it was , but the gammie said it wasn't legal and cited him.
My son almost got cited for stacking nickles in his tube. The weight diff. caused his tube mount to fail when he fired at a goose, the tube separated from the gun. There were nickles everywhere in the blind.
The gammie thought it was funny , but explained the rule to him, with no citation.
80$ later, gun was fixed.