I purchased a rifle "turkey" sight for my sons 870 20ga. I did not see that it said I had to remove the factory front bead for this one to fit. I have now realized that it is not a screw in bead. How do I remove this "pressed" on bead? I am trying not to damage the guns finish. I am not a guns smith, but have done small stuff like this and scopes etc befreo. However I cannot seam to get this thing to budge. It is a vent ribbed barrel. Any ideas? Thanks,