I have a Nikon Pro Staff 2-7x32mm on my White Ultra Mag and love the scope. Although if you're trying to stay in a budget, it will put you over a little as they run about $129.00

Actually there is nothing wrong with a 3-9x40mm just make sure to check the eye relief. You want to find one with about 4" of eye relief. I have a 1.5-4.5x32mm Bushnell Banner Dusk to Dawn on my Black Diamond XR and it would be a good 150 yard rifle. The advantage of the higher power would be on the target range. I havea Sightron S1 and a Millet Buck on a different one. Both of them are 3-9x40mm and they are great scopes as well.