22CAT,I just Installed a beard buster on my 12 guage stevens,the rear sight sandwiches between the vent rib and the front sight screws in where the front bead unscrews.the rear sight screws were a little long and bottoming out on the barrel,so I just used 4 washers and that did the trick. very good for low light and leveling out on your target.$16.00 amazon good luck