Have used both the Warne and Weaver front extension bases with shorter scopes on 98's. I shortened the back end on them a little so they didn't hang over the port--more nearly flush with the receiver ring and it then moves the front scope ring back enough for me. The Warnes are lower bases than the Weaver, if you have higher rings or vice-versa. Too, have used a Rusan front extension ring. They do have have more and wider ring slots, though, than the other two.
