Scope Adjustment Range from Its Zero Setting

[Bart B.]

Have any readers measured their rifle scope's adjustment range from its optical zero settings?

In other words, once the scope's windage and elevation settings are zeroed by the:

* V block (spinning scope as it rests in two V blocks adjusting W and E knobs to get reticle to stay at one place)

or

* mirror (placing scope objective end on a mirror then adjusting the knobs so the reticle images superimpose)

methods, how many click units are there from that zero to the adjustment limits in both directions? Midpoint between the knob's physical stops is not the optical zero.

Note that a lot of scopes' knobs will continue to move out and click while the scope's inner tube is stopped against the outer tube and the reticle doesn't move when the knob's turned counterclockwise (windage adjusted to the right, elevation adjusted up.) And springs between the inner tube and outer tube prevent the inner one from moving as far left and down compared to up and right by the windage and elevation knobs.

The ones I've checked have about 1/3 of their range down and left from zero, 2/3 from up and right. And a few to several MOA of "no movement" at the upper and right limits of the knobs. I think the inner erector tube's stopped against the outer main tube but the adjustment still has room to go before reaching its stops.

I'm thinking about making a chart with lots of scope's limits. But I'd need a lot of input from people willing to "measure" their scopes then send me the data.

Comments welcomed.

 

[Rob01]

Never have as it doesn't matter to me. The only thing that matters is how much I have once I bring it to the range and zero the scope and then how much I have as that is what I need to dial my data.

Scope manufacturers are pretty good with giving the overall elevation and wind age data so I don't see a need.

 

[Bart B.]

Scope manufacturers are pretty good with giving the overall elevation and wind age data so I don't see a need

I agree; they give some data. But I've never measured a scope that matched its data stated in their published specs. And none of their optical - mechanical zero point was in the middle of their published specs.

 

[Ggmac]

I usually have my scopes rotated 90 deg . Elevation is now windage . I started doing this 20 plus yrs ago , just to have the ejection port unobstructed for single loading and I could use my left hand to adj windage without breaking position .
OK it was probably 30 yrs ago , using the Redfield 3200 . Dang it seems like just last month .

 

[Rob01]

I agree; they give some data. But I've never measured a scope that matched its data stated in their published specs. And none of their optical - mechanical zero point was in the middle of their published specs.

They are usually more so no issues there. Also they all might not be the exact same so some data base data will be useless. People will get at least what the maker specs and that is what they make their decision from.

 

[ChrisNZ]

.. none of their optical - mechanical zero point was in the middle of their published specs.

This is most probably your mounting system at fault- rings aren't necessarily aligned to the bore.

 

[Bart B.]

I'm not comparing mounted scope axis on rifle to bore axis. That's a measurement of the scope base and rings' axis to the bore axis as determined by barrel tenon thread axis in the receiver shape and screw hole positions. Of course, they are sometimes X MOA misaligned. I've measured a few and Rugers were the worst of the receivers I checked.

Just where the scope's optical center its inner tube is to its movement limits in elevation and windage while you're holding it in your hands.