Contender scope mount

Does anyone know if there is a very long scope base for 16" contender barrel that will fasten in the four screw holes near the chamber and extend all the way to the rear iron sight tapped holes for securing the front end? I have a hard kicking 358jdj and I want to shoot it as a rifle and I need to get an extended eye relief scope far enough forward to mount for the proper eye relief. With a normal 4" eye relief rifle scope I cannot keep it from hitting my eye in recoil.