Beretta A390 with 1/4 choke,any 3o gr No 6 fibre wad. I use this gun all the time for my pigeon shooting as i always used to catch my nets with an O/U.
I've got a 390,a great gun- I use it for everything. I am not familiar with the 3901 but having owned a 303 in the past I would agree that any Beretta semi auto is a good gun.