I know what you're talking about. My Nikon Buckmasters are the "poster children" of tunnel vision: put my 6-18x up against my Sightron 4-16x SII Big Sky and it's like looking through a 1" pipe compared to - well, the sky - the Sightron's view is that much more spacious and edge-to-edge. Thought it might just be a problem with side-focus scopes at first, but it seems to be an issue with fixed-parallax and AO, too. In fact, I was ready to buy a 6-20x Weaver Grand Slam before they are closed out; read on another forum of that otherwise fine scope's tunnel vision and that was a deal-breaker for me. Might not bother some people, others might never notice the difference if it's not pointed out.