Questions about scope adjustment range/reset turret to zero

sonichanxiao

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I am wondering after mounting the scope on rifle, zeroed, (assuming many people will reset the windage and elevation turrets to zero on their scope) does this turrets reset process change anything internally such as lens position, turrets adjustment range etc.?

e.g. a FFP scope with 30mil elevation and 10mil windage described in the specs.
1. Ideally, if the scope lens is at the center point after zero, that means the scope has 15mil up and down and 5mil left and right adjust available(Half of the 30mil elevation and 10mil windage adjust listed in the spec)?
2. In real case scenario, say after zero the scope, the turrets adjust are 5mil up and 2mil left, (before reset turret to zero) does that mean we have 10mil up(15mil-5mil), 20mil down(15mil+5mil) elevation and 3mil left(5mil-2mil) and 7mil right(5mil+2mil) windage available from this point now?
3. Based on question 2's adjustment, 5mil up and 2mil left zero, if we reset turret to zero, anything inside the scope moves/changes? I am guessing, the new zero reading on the turrets reset to 0mil elevation and 0mil windage, but actual adjustment underneath is still 5mil up and 2mil left?

Try to understand how the internal mechanism works after reset turrets.

Thanks in advance.
 

DarnYankeeUSMC

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To your first point.
If you set your zero at 100 you most likely will not be centered of your available adjustment.
You hopefully will be towards the bottom giving you more elevation adjustment.
All scopes, rifles and mounts are going to vary. So once you get your zero and reset your turret cap. You then can run it up to see what elevation adjustment you have available in your setup.

Or something like that. Maybe someone else will come along and explain it better/different
 
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Huskydriver

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2.) Yes this is correct.

3.) When you "zero" the turret, all you are doing is slipping the outer turret back to your zero reference mark so any changes you made prior count towards your scopes total travel available like you calculated in #2.

@wade2big is exactly correct in why we run 20-40 moa rails under our scopes if you plan on shotting past 1000 yards for *most calibers.
 
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sonichanxiao

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2.) Yes this is correct.

3.) When you "zero" the turret, all you are doing is slipping the outer turret back to your zero reference mark so any changes you made prior count towards your scopes total travel available like you calculated in #2.

@wade2big is exactly correct in why we run 20-40 moa rails under our scopes if you plan on shotting past 1000 yards for *most calibers.
Thank you.

1.So if all the scopes manufactured with lens are exactly centered when elevation is 0 and windage is 0, I can understand after mount the scope(assume 0 base/mount are used), we adjust elevation to zero the scope with rifle at 100yard/meters, but why windage adjustment is also involved? Does that mean scope is a defect product? Or it just means the lens isn't set to center when windage and elevation is at 0 mark in the factory?

2.The image in my mind is like after we zero the scope on a 0 base/mount rifle, adjustment made is 5mil up and 2mil left. The position of the internal lens could be something like 3mm to the top and 1mm to the bottom(lens moving downwards to lift up the muzzle), and maybe 1mm to the left and 2mm to the right(assume lens moving left to adjust windage to the left) . At this moment, if we reset the turrets, nothing will change inside, the position of the lens won't move, only the outer turret reset to 0 mark on the reading, right? If this is the case, the lens inside moved towards 8o'clock direction comparing to the center point to be zeroed at 100?

3.Based on question 2, the available elevation and windage after zeroed scope and reset turrets back to 0 mark, would be less than the marking on the scope, right? e.g. after 5mil up and 2mil left zeroed scope(30mil elevation/10mil windage as listed in spec), the actual elevation available after reset turrets could be only 20mil, even the turret marking may have 25 mil adjustment from 0 and windage after reset turrets could be only 3mil available to the left, even the turrets marking has 5mil on each side after reset to 0, correct?
 

gunsnjeeps

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1. Mechanical centering of the scope over the bore centering of the reticle in the tube. Difference in ring height or mount is not flat. Barrel not inline with receiver. Difference in cheek weld from person ti person.

2. You are zeroing your knobs to a reference zero. Say 100 yard zero. At 200 yards you may need to go up a minute and left .5. At 300 up 3 and left 1. You are determining your zero for each range and recording the change from your 100 yard zero. Internal elevation will be your limit to range adjustment. Constantly adding windage with range means your scope is crooked. In you question if I zero at 100 adjust to 200 and reset the zeros on the knobs my zero is now 200 yards because that is where you parked the reticle

3. Yes internal mechanical limit determines how far it can move. The knob number is for you to know how far from 100 yard no wind 0 you moved. If you change the zero to 200 yards you can still only add range until you hit an internal stop.
 
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sonichanxiao

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1. Mechanical centering of the scope over the bore centering of the reticle in the tube. Difference in ring height or mount is not flat. Barrel not inline with receiver. Difference in cheek weld from person ti person.

2. You are zeroing your knobs to a reference zero. Say 100 yard zero. At 200 yards you may need to go up a minute and left .5. At 300 up 3 and left 1. You are determining your zero for each range and recording the change from your 100 yard zero. Internal elevation will be your limit to range adjustment. Constantly adding windage with range means your scope is crooked. In you question if I zero at 100 adjust to 200 and reset the zeros on the knobs my zero is now 200 yards because that is where you parked the reticle

3. Yes internal mechanical limit determines how far it can move. The knob number is for you to know how far from 100 yard no wind 0 you moved. If you change the zero to 200 yards you can still only add range until you hit an internal stop.
Wow, thanks a lot for your detailed explanation.

I got all the answers. Thank you sir.