I have an h&r single shot turkey gun. It's a few years old as they're no longer being made. Plain barrel, just a bead when I bought it. I wanted a rail but couldn't justify the cost to have it drilled and tapped relative to what I paid for it. Also, a gunsmith told me it would be tough to do it since the barrel is so thin. What I did was put a two piece Williams ghost sight on there with jb weld. Removed the bluing and cleaned it up real good before I glued it. Have killed quite a few turkeys with it in the last few years. Seems like it won't budge anytime soon. Fingers crossed