Drake, I have the Nikon 50mm ED and love it. For a couple reasons.
It has the ED glass, its totally waterproof, and only weighs 19oz!!!! The best part is the size and weight. When your packing a weapon, the bigger scopes usually get left behind because of the added bulk and weight. But its no big deal to pack the 19 extra ounces instead of the 4-6lbs (or more)that the 60-82mm guys add. Stay with the 13-30x. With the 40x the added power is severly compromised because of the 50mm objective.(1.2mm exit pupil)very poor in low light. You are dang sure not going to be able to pick apart an animal at a mile, but its enought to be able to see if its something that is worth getting a closer look at. Saves some wear and tear on the legs anyway.
Hope this helps.
