I have no links, but i'll try to help you ouy anyways. The 40mm compared to a 50 mm lens has one benifit. It can be mounted lower on your rifle. The 50mm will give you a wider field of view, compared to the 40 at the same magnifacation. The exit pupil on a 50mm set at 18 is 2.7mm. The exit pupil of a 40mm set at 18 is 2.2mm. Thats how much light is reaching your eye. So in theory, the 50mm will appear brighter in lower light. But if that's your primary reason for buying one, don't. Your not shooting your .22 in the middle of the night. I'm familier with both scopes your looking at, and I have owned the 6-18 Banner. It is a nice scope, but makes things a bit top heavy. For the money, the Tasco is still a good deal, complete with a mil-dot reticle, but I'd buy a banner if I were you. The adjustable objective works well on rimfires. You can dial it in to give you the best sight picture at various ranges. I even used mine as an impromtu range fnder. Buy dialing it out until my target and crosshairs came into alignment, it gave a pretty good reading in distance out to just over 200 paces. You'll probably like that. Good luck with your desicion.
