Spruilldog:

I too have a Marlin .30-30, andmounted on it aLeupold VX-1 2-7x32 about six or seven years ago. I beleive that their 4X fixed is about the same size -- I usually just leave my scope on 3x or so. I love that combo. There's plenty of eye relief,and it'sa clear, rugged, and dependable scope. I mounted mine with a one piece Leupold base, and low rings. I don't have much familiarity with the Weavers, so I can't help you there.