You are on the right track with a Leupold 4x. I've come full circle back to mostly fixed power scopes. You will find a 4x perfectly fine on even long shots at big game. I'm also a big fan of the Leupold 6x36 as my eyes are no longer what they used to be.
The first high power metallic silhouette match ever held in the state of Missouri (August 1979) was won with a 30/06 on which was mounted a Leupold M8 4x28. I had no problem holding on the 500m rams nor on the 385m turkeys.
