How to adjust zero

[YetterIsBetter]

In a perfect world I'd zero my optic at 100m on a flat range. I don't have that. What I do have is a 100 yd range on a slight upwards slope. The target sits about 20ft higher than the shooting position.

How can I adjust my zero to be a true 100m zero after having zeroed it on this less than ideal range? How do I figure out how many inches up or down I should adjust?

 

[_Windrider_]

I wouldn’t adjust it. That isn’t going to change a darn thing. A simple Pythagorean formula will tell you it’s 300.66 ft.

You will never ever be that accurate to need to worry about it.

 

[Deadmanwalkingslow]

In a perfect world I'd zero my optic at 100m on a flat range. I don't have that. What I do have is a 100 yd range on a slight upwards slope. The target sits about 20ft higher than the shooting position.

How can I adjust my zero to be a true 100m zero after having zeroed it on this less than ideal range? How do I figure out how many inches up or down I should adjust?

I had the same situation, almost to exact elevation. I sighted in numerous calibers for various purposes and found no problems of any significant.

 

[Taylorbok]

The difference we are talking about here is under .1 mil so you can't even adjust it out. If you are zeroing and have to choose between being a blonde one low or high go with high.

 

[ptosis]

The generic answer is: use a ballistic calculator to check how many clicks you need to make with your rifle zeroed at 100m to be poa=poi at your available range. (And -- yes -- chances are that in your specific case it will be within 0.1 mrad.)

 

[BuildingConceptsllc]

And this is why MOA is superior......

 

[pmclaine]

I wouldn’t adjust it. That isn’t going to change a darn thing. A simple Pythagorean formula will tell you it’s 300.66 ft.

You will never ever be that accurate to need to worry about it.

Look at the brain on Dillhole.

My kids recently asking me why they need to know how to solve for X....and professor Dillhole knows.

 

[pmclaine]

And this is why MOA is superior......

Why is anyone zeroing at meters anyway? This is GD America!

You know your mil scope is independent of your unit of lineal measurement?

 

[BuildingConceptsllc]

Why is anyone zeroing at meters anyway? This is GD America!

You know your mil scope is independent of your unit of lineal measurement?

Exactly right....! I couldn't help myself this morning. The opportunity was too easy...

 

[_Windrider_]

Look at the brain on Dillhole.

My kids recently asking me why they need to know how to solve for X....and professor Dillhole knows.

Not to mention that the distance affecting drop is still 300 feet. That additional 8” is the wind distance.

 

[Mike Casselton]

Why is anyone zeroing at meters anyway? This is GD America!

Cause the gol dang Army talks in meters, feet and inches...

 

[pmclaine]

Cause the gol dang Army talks in meters, feet and inches...

McCarthy was right!

 

[Aftermath]

McCarthy was right!

So was MacArthur.

 

[pmclaine]

So was MacArthur.

Imagine how he would have changed the take out industry.

 

[acudaowner]

I liked the set it at 100 yards then forget it , 4 years later have not had to play around with it yet . I do have to remember to return my wind to zero after each use . I shoot on a windy day and adjust it then forget have to recenter it on low or no wind days I am horrible at remembering to do that being lazy and forgetful is horrible ..