Roscoe,

It's a catch 22. On my rifle the objective stops at the flip-up sight. The solution is a 30mm or 1" straight tube with low mounts or higher to clear the bell.

The eye relief on mine is spot on at 2X, which is ok on a .458 wm.

Here is the perfect Ruger Number 1 scope.

http://www.midwayusa.com/viewProduct/default.aspx?productNumber=791324