Floating was allowed by design in older Benellis. I recall an old HK video that shows how a Benelli can cycle even with a shell on the carrier. It was clearly an intentional feature.
Benelli made a remedial alteration to the bolt at some point in order to prevent floating a shell. This modification can be reversed by several mechanical methods.
There is some speculation as to who asked Benelli to do this. Might have been USF&W. Might have been no one. They might have been responding to customers who were cited for floating. Who knows?
A Benelli with the modification, that is plugged to hold only two in the magazine, will satisfy the federal law requiring a waterfowling gun to hold no more than three shells. Of course, you can float a shell any time it is legal.
mudhen - CA
"Lighten up Francis"