This rail is perfect for the 870A. However, it does not fit the Super Mag right out of the box. Because of the longer carry in the charging stroke, you have to do some moderate modification before it will fit the super mag. You either need to trim down the rail or cut about a 1 inch notch in the fore-end. I chose to use my dremel tool to cut a notch on each side of the synthetic fore-end charging grip, that did the trick. The rail works great, after the modifications.
Pros: Well made, solid, custom fit
This review was written in the old system and had content requirements that are different than reviews written today.