Since the wad is longer in the 3 1/2″ shells we have made the tube longer to maintain a tight, dense pattern. This tube can be used with 3″ or 2 3/4″ shells also for a tight dense pattern. Patternmaster’s 12ga Benelli/Beretta Mobile tubes will interchange with Benelli M1, M4, M3, Sport (After 2006), Nova, Super Nova, and Super Black Eagle. Beretta USA’s A300, Silver Pigeon, White Onyx, Ultralight, and Diamond Pigeon. There are other shotguns that interchange as well like Stoeger 2000 Semi-Auto, P-350 Pump, and the M3500, Franchi current production shotguns, Legacy Escort, Huglu, CZ USA, Hatson, some Charles Daly Models, Mossberg Silver Reserve, Savage, Smith and Wesson current production, Traditions Semi-Auto, and Tri-Star Phantom Field and Silver Series, just to name a few. For more information about your shotgun interchange please see the firearm owner’s manual or contact the firearm manufacturer.