Paul, the barrel has nothing to do with it. The chamber size is what counts. If the chamber can fit up to a 3.5" shell then you can use shells from 2.75" up to the 3.5". If your using a model 500 then you need a barrel for a model 500, same goes with a 835, 535, 935, etc. you would need the barrel that was made for the model. Here is a link to barrels made by Mossberg for each of there models......

http://www.mossberg.com/products/acc...section=access