Trijicon 5-20 Question

[twwilson]

Hey guys I have a friends AR10 with a nice Trijicon 5x20x50 on it. He said it was close but wasn't sure it was dead on so I told him I'd get it zeroed and give him a drop chart for 100-700yrds. I do not have any experience with this scope previously. I went out and got it dialed in at 100, he was fairly close but I failed to notice where I was in the scope.

I plugged in the ballistics info and got a dope for 400 and went to adjust. I had hit the top end of the range of the scope. Now, I assume since I've never dealt with this issue starting off, that I'll have to start back over with the turret all the way down but I'm wondering if I'm on paper at 100 with the turret all the way up, how does it zero again at 100 at the bottom? Just trying to think it through logically. I'm going back out tomorrow to test.

Thanks for any input.

Tyler

 

[twwilson]

I can't be the first person to experience this. It may be the dumbest question in the world pertaining to sighting in but I've never dealt with this before. Just looking for some thoughts. In my mind, if I'm zeroed at 100, at the top end of the range adjustment, how can I adjust all the way to the bottom, and then zero again? That particular scope has 40 MOA of travel. If I'm zeroed at 100, already at 39MOA in adjustment travel on the scope, how does it then zero again at 100, when I back it down -39MOA? Maybe I'm just not thinking about it correctly.