My father in law has a mossberg 500, 24'' fully rifled 12 ga, but its not one the new Slugsters. Took it out today and found it only holds 2 shells (2 3/4) in the mag tube. I've seen the newer advertised to hold 4+1. Now, I havent taken it apart to look at it nor have I had the chance to ask him about it. I'd like to buy it from him in the near future but I want to know if this is suppoed to be like this or not, figured I'd throw it out there and see if anybody in the forum could help me with this.