I bought a 12ga turkey barrel with screw in choke as an accessory barrel. On my order form I asked that they drill and tap it for the scope rail. When I got it back, no drill and tap but the rail & screws were in the box. I called and they said they don't do the drill and tap. So I went to the gunsmith at Gander Mountain. He said the chamber was too thin for him to drill and tap. So I just used the rail on a different barrel.