Lodgepole: If I recall correctly parallax of fixed power Leupold scopes for centerfire cartridges is factory set at 150yds. I leave mine set at 100yds but, most of my shots (95%) are under 200yds so its not going to matter enough to cause me to miss on a groudhog and larger game.
I haven't found a really GOOD, short, not too technical article on scope focus and parallax. These links might cause a little "information overload". But, they should help.
Remember this: Properly adjust your focus FIRST! Now, leave it alone!!! Unless... you get glasses, new glasses, or reach about age 40 when our eyes start to change.
Parallax matters. But, is not as important/critical for normal range hunters as it is for long range hunters and target shooters.
This may help.
Read this first: http://www.snipercountry.com/Articles/Parallax.asp#Parallax
Read this second. http://www.6mmbr.com/parallax.html
There's some good info here. http://www.rimfirecentral.com/forums/showthread.php?t=496141
