Actually I think you mean to say that the Nikon is "parallax free at 100 yards". It means that at 100 yards no matter how you move your head around (side to side or up and down)behind the scope, the reticle will stay centered on the same spot, assuming you don't move the scope itself of course.At any other distance, say 200 yards, you will notice that as you move your head around, the reticle will also move somewhat relative to the target.For big game huntingat sane ranges parallax is not anissue to be worried about.Forprecise target shooting and maybe long range varmit hunting, it can be a problem. In that case you would probablywant a scope with an adjustable objective or side focus adjustment.

BTW, let me add thatscope manufacturers may use a different distance than the 100 yards that Nikon apparently uses for this particular scope. For instance, I believe my Zeiss Conquest 3-9x40 is set to be parallax free at 150 yards. Like I mentioned above, though, for 99% of big game hunting, parallax is a non-issue.