Returning mechanical zero (factory)?

[Jdock19]

How do you guys return a scope to factory zero?
Can i run the turret all the way down then count the clicks it takes to run all the way back and divide that in half?

[Ol` Joe]

Yes.
That is how I was told to re-zero a scope

[JDG]

I have a wooden v-block fixture, that I use.

[04JRB]

How do you guys return a scope to factory zero?
Can i run the turret all the way down then count the clicks it takes to run all the way back and divide that in half?

That is the way I have done it when buying used optics and want to find the true mechanical center of the erector system, before sighting it in to what I installed it on at the range. Tedious, but it does work.

[50 BMG]

You can check your results by using 2 semi-skinny pieces of wood on top of a good table.
they need to be equal thickness and tall enough to clear the turret heights.
situate the wood close to and parallel to the edge of the table so they are like "rails" that will support the scope's main tube only (on opposite sides of the turrets but inside the objective lens & eyepiece bells). Now, with the eyepiece close to the very edge of the table, kneel down next to the table and slowly Roll the scope along your rails while looking through the eyepiece to see if the reticle center has any "wobble " to it as the scope rolls. If it does, adjust the turrets slightly until there is no wobble visible and that will be the perfect "center" of the reticle in relation to the scope tube itself.

[Ol` Joe]

https://www.youtube.com/watch?v=-A3GwfB0Yg8

[Viking]

We used to mechanically Zero sight posts and optics that were too far off or to reset to base for when transferring to someone else, align all the way to left, (or right, or up or down) then carefully count every click to the opposite end, hopefully it is an even number, then return to half of that number. Remember your starting point at zero is one of those numbers if something ends up seeming off or odd. However if you continue to have a problem with the scope adjustments, (theoretically?) in scopes you have to remember the internal construction of the aligning screws will sometimes especially in older scopes, require overturning and then backing up or tapping to allow inner optic tube to align to follow the alignment screws backing away from the tube, which is why in the past military units sighting in scopes would tap the scope with a magazine after every adjustment during zeroing. This was theoretically caused by the inner optic tube NOT following the screws when they back away, causing a round or two of the next group to run astray. I am told though that this doesn't happen in newer scopes anymore ... but I'm not sure.

[50 BMG]

https://www.youtube.com/watch?v=-A3GwfB0Yg8
Clever....

[50 BMG]

However if you continue to have a problem with the scope adjustments, (theoretically?) in scopes you have to remember the internal construction of the aligning screws will sometimes especially in older scopes, require overturning and then backing up or tapping to allow inner optic tube to align to follow the alignment screws backing away from the tube, which is why in the past military units sighting in scopes would tap the scope with a magazine after every adjustment during zeroing. This was theoretically caused by the inner optic tube NOT following the screws when they back away, causing a round or two of the next group to run astray. I am told though that this doesn't happen in newer scopes anymore ... but I'm not sure.

Another good point to bring up Viking...
As a extreme range .50 shooter, we still run across similar issues with very modern/very expensive scopes (Nightforce, Leupold MarkIV's etc...) quite often.
The problem, as was explained to me, was that most of us don't articulate our scope dials enough to keep the factory installed lubricant distributed evenly on the internal reticle erector assemblies. Essentially, gravity will make these lubricants congregate to there the erector is at rest. So, when we try to move them, they temporarily will "drag" on the excessive lubricant, to eventually settle in at the desired setting once the excessive lube has been displaced (that is what the tapping on the scope will help accomplish).

The fix for this is to turn your scope adjustment knobs/dials a few full rotations in each direction before needing them to work "spot on" and accurately when the time for smaller adjustments arises. Most of us .50 shooters will be seen turning our elevation and windage adjustment knobs a few full rotations back and forth before a 1000yard match begins. Since my MkIV scopes have 140MOA of adjustment internally and they are mounted on forward slanted bases which range from 30-45MOA themselves, I can be found turning my elevation knob 5-6 full rotations up and back before trying to zero at 1000yards from my normal 200 yard zero (unless a rifle is already zeroed for 1000yards, we have 35-40MOA; 140-160 clicks for a 1/4MOA knob, to adjust to get on target at 1000yards anyway).
Don't be afraid of turning your knobs back and forth as described. It does make the smaller adjustments work better/more accurately.
A good quality scope will always return to zero no matter how much you manipulate the knobs, as long as you know where your close range zero is on your knobs in the first place (that's why knobs that zero-reset are so nice; you don't need a good memory to re-find your close range zero).
;-)

[Viking]

Thanks 50, learned something new on the overturning/returning adjustment knobs, I haven't had the pleasure of shooting past 600ish with anything that HAD an optic.