I just had the good fortune to get a new Beretta 303 in 20 gauge. It is a 1987 DU dinner gun in 3" mag. It works perfectly with all hunting type loads but will not cycle 7/8 ounce shells. Does anyone know if the Winchester 1 ounce heavy trap load will cycle in my gun. I don't want to open the gas port as I want to be able to still use the heavy hunting loads. Any suggestions would be great.