I have had my share. One that really bugs me is back during my coyote hunting days.

When one becomes totally familiar with their weapon, it is second nature when it comes to the hunting field. Oh, the safety precautions, target aquisition, background, muzzle attention, loaded/unloaded, etc. etc. are still all in place, no problem.

I am talking when actually putting that sight on the quarry for the final trigger squeeze. Well, I was so used to my scope setting for killing coyotes that one time I sneaked up on a bedded coyote; he was in a snow bank and REALLY OBVIOUS. Also really obvious was that I had all the time in the world to get set up and squeeze the trigger, as he was fast asleep. (You know; it's called "the gimmee...")

Well, my tried and true duplex Leupold reticle told me he was 400 yards away, even though I swore he looked a whole bunch closer. So I held for 400 and saw the snow erupt several inches above his back. He jumped up and hit full power plus afterburner in less time than it takes you to read this. Bye bye to an easy $50 dollars for his pelt.

I then suddenly realized/remembered that I had dialed the variable power scope down to a lesser power while "screwing around" for some reason and forgot to change it back. And that mistake changed the whole relationship as far as judging range with the duplex reticle!!!