Were you carrying the rifle slung or strapped to your pack? Either way at least now you will always check and not have that problem anymore.That was my blind assumption from the start - but I have learned otherwise. The mechanism that prevents the turret from going "backwards/down" past zero is rock solid - no real way to move without a hex key, but the little silver button that prevents moving "forward/up" is easily depressed. I assume it was rubbing on something on my MR pack enough to have depressed and moved one click. After the first click is achieved no further manipulation of the silver button is necessary to continue to advance the turret. It's a one time error, and one that would only occur with a point blank shot, otherwise I would have been purposely working the turret. Going forward I will always take a quick glance when setting up a shot even if not needing to dial - problem solved - and since tag punched anyway no harm no foul in my case.