What I did to mine was add a Scalarworks mount and T2, Nordic plus 2 (as the Benelli extension has a thingee that can be dislodged turning your shotgun into a one shot).
What is the issue with the factory tube? Any more details?
What is the issue with the factory tube? Any more details?
Unlike the Nordic, which is a solid tube, the end of the Benelli extended tube is open, with the spring retained by a thin metal plate. If you push on that plate wrong, it dislodges along with your spring.