i just got a couple of shotguns back from a buddy i loaned him so he could take his sons goose hunting. one is a 500A one is a mossberg 88. he has a 500A also. we were talking about breaking guns down for cleaning, as steel loads will really gunk up a shotgun. he told me he is looking for a tool that will help him disassemble his slide, and here's what i use: the back of the file on my multitool. a lot of folks buy unnecessary tools for this type of stuff when you usually have what you need on your belt already. just place the back of the file in the grooves of the ring that holds the forend on and screw it off. figured i'd put it up here thinking it might help someone out. this works on any pump shotgun i have, mossbergs, remingtons and winchesters. i hope this can help somebody.