Setting Mechanical Zero

[Nefarious]

Optic is my NF 8-32x56mm (1/4 moa)

Total Elevation Clicks = 241 (got an odd number??)
Total Windage Clicks = 168

Divide those in half and I get
120.5 elev
84 windage
So do I simply click backwards - or forwards depending on which way i went the first time - and this is my starting "Mechanical Zero"?

Side Note
NF claims 65moa elev and 45moa windage
but by my numbers above .. dividing by 4 gets me 60.25moa elev and 42moa windage ...

[ar15barrels]

NF claims 65moa elev and 45moa windage
but by my numbers above .. dividing by 4 gets me 60.25moa elev and 42moa windage ...

Did you count the elevation clicks with the windage centered and vice versa?

I would personally set the scope on a set of v-blocks and rotate it round and round while adjusting the reticle so that it's not making a circle as I rotate the scope.
This would ensure that the reticle was optically centered in the reticle.
Then I would adjust the bases for windage if such an adjustment existed.
This would put the reticle in the middle of it's windage travel, ensuring that the maximum amount of elevation adjustment was available and that the scope was sitting straight over the top of the barrel/action.

[Prc329]

Use the US Optics instructions on there website.

http://www.usoptics.com/video/centerhi.wmv

That will "mechanically zero" your scope.

[ar15barrels]

Use the US Optics instructions on there website.

http://www.usoptics.com/video/centerhi.wmv

That will "mechanically zero" your scope.

That's exactly what I was saying to do.
I like the simple idea of using the scope mounts to do this, but I'm not particularly fond of spinning the scope in the mounts and making marks on the scope.
I know it won't matter on type III anodized US Optics.
That scope will just put scratches on the steel mounts!
On a type II anodized scope tube, you will have marks on the tube from doing that.

[Nefarious]

Was the reticle ... loose in that video? I mean, by spinning the scope, were the crosshairs floating around in there and moving by the spinning? Then from there your using the turrets to "click" back to center?

I really dont know much about scopes, but what needs to be lossened to get the reticle to do this? The Nightforce has the set screws to zero out the knobs/turrets .. but that does not get the reticle to flop around like that. It just removes the click adjustements so you can freely spin the turret. I have removed the knobs/turret, but did not notice any other adjustment screws - from what I remember

Im looking now at the Nightforce webapge to see what I can find.

[ar15barrels]

Was the reticle ... loose in that video? I mean, by spinning the scope, were the crosshairs floating around in there and moving by the spinning? Then from there your using the turrets to "click" back to center?.

The reticle is not loose.
It's controlled by the windage and elevation turrets.
Just look at exactly what he's doing in the video.
When you see the reticle being moved up and down, he's turning the turrets to do that.
When you see the reticle rotating, he's spinning the scope to do that.
Notice at the end that the reticle is still rotating, but it's rotating about the same point on the grid.
When you see that, you have the reticle in the center of the scope.

Once you get the reticle centered, mount it and zero it.
Then re-set the turrets to zero to reflect your proper zero.

[Nefarious]

The reticle is not loose.
It's controlled by the windage and elevation turrets.
Just look at exactly what he's doing in the video.
When you see the reticle being moved up and down, he's turning the turrets to do that.
When you see the reticle rotating, he's spinning the scope to do that.
Notice at the end that the reticle is still rotating, but it's rotating about the same point on the grid.
When you see that, you have the reticle in the center of the scope.

Once you get the reticle centered, mount it and zero it.
Then re-set the turrets to zero to reflect your proper zero.

It looked like when he was spinning the scope, that the reticle still had some movement when he stopped I could hear him clicking to adjust the turrets - after I turned up the comp speakers a little more. I suppose you would infact need a boresighter to center using the method in the video

[ar15barrels]

It looked like when he was spinning the scope, that the reticle still had some movement when he stopped I could hear him clicking to adjust the turrets - after I turned up the comp speakers a little more. I suppose you would infact need a boresighter to center using the method in the video

If the rifle is sitting steady in some sort of rest, you can use a spot across the room/yard as well if you can focus that close.

[Nefarious]

If the rifle is sitting steady in some sort of rest, you can use a spot across the room/yard as well if you can focus that close.

Thanks for the info.. ill give it a try as I get home.
I know most people say a boresighter are a waste of money... but for me, it might be worth it untill I learn a little (or alot) more about sighting in scopes. Yes yes people say "just look down the barrel" ..

[ar15barrels]

people say "just look down the barrel" ..

That's how I do it.
Put a target up at 50yds.
Get a solid rest so that you see the target down through the barrel.
Adjust the crosshairs on to the target.
Begin shooting and adjust as necessary.

[Prc329]

That's how I do it.
Put a target up at 50yds.
Get a solid rest so that you see the target down through the barrel.
Adjust the crosshairs on to the target.
Begin shooting and adjust as necessary.

Then move to 100 and make any adjustments needed.

Why would you need to center the erector if you are going to zero the scope and knock it off center anyway?

[ar15barrels]

Why would you need to center the erector if you are going to zero the scope and knock it off center anyway?

Windage adjustable base.
Or to confirm if your base is straight to the bore.

If you center the windage, fire a shot and it hits the center of the windage, everything is straight.
If it hits way off to the side, it's time to correct the mounts before you simply offset the scope to account for it.

[rksimple]

Windage adjustable base.
Or to confirm if your base is straight to the bore.

If you center the windage, fire a shot and it hits the center of the windage, everything is straight.
If it hits way off to the side, it's time to correct the mounts before you simply offset the scope to account for it.

Isn't it nightforce that recommends against windage adjustable bases/rings? Something about torquing the scope tube...I'll have to look.

It happens more frequently than we'd like that the holes in the receiver are drilled improperly and not aligned with the bore. This really needs to be corrected by drilling out the holes for 8-40 screws and centering them up rather than windage adjustable hardware. This is also assuming that your base and/or rings are not the culprit.

[Nefarious]

I thought I read something about that too..
Thats why I went with their Unimount in the end -

[ocabj]

From the setups I've seen, I rarely see anyone using a windage adjustable base.

Ideally, you really should since you want the maximum amount of windage adjustment available, especially if you are a long range shooter. The concept of setting a mechanical zero for the reticle (at least for windage) is the same concept iron sight shooters use when maximizing windage adjustments available on the rear (setting the rear sight to mechanicall center and setting the no-wind windage zero by adjusting the front sight).

Anyway, I hardly ever see anyone using a windage adjustable base (or rings) on long range guns. Most people rely on 'luck' (and holdover) when they need more windage at long range in high wind with standard base and rings. Whether or not this is the right way or wrong way, I'm not doing to debate.

As far as windage adjustable bases and/or rings being bad for the scope, yes, that is possible due to binding. There are ways to minimize (and even eliminate binding) in this type of setup using a lapping bar.