Thats really good advice. Yes, mounting something to the tube, you have to be careful. Lucky mine is solid as a rock and the tube un-dented. With the way it feels now and with loc-tite on the screws, if it comes loose; I'll probably just go to a forearm one. I don't want something coming loose and its already less that ideal, but still works, at least mine does. I've got an 870 with a light too, so its not as crucial if my 500 light mount fails either. Especially when it just sets in the corner, inside and I'm not exposing it to rough range/field use.
You don't need to take off the rail, if you want to change barrels though. Its only in the way, if you want to take the forearm off.
"No free man shall ever be debarred the use of arms."- Thomas Jefferson