Changing Zero
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Changing Zero
Normally when we first get to the range before a match, I check the "chicken zero" on our rifles for the day as I clean my rifles after each match. Usually I shoot a few shots to "warm" the barrel, but the guns start right off shooting very small groups.
I have noticed a 1 MOA change in zero from mornings to afternoons when checking zeros before a match and again between matches in the afternoon. The morning's zero's being 1 MOA lower than the afternoons. Our original assumption was changing temperatures. Honestly I need to start writing down the temp and humidity and where the "chicken zero" is at specific times to try to determine what is causing this.
Has anyone else noticed this and have an explanation?
George
I have noticed a 1 MOA change in zero from mornings to afternoons when checking zeros before a match and again between matches in the afternoon. The morning's zero's being 1 MOA lower than the afternoons. Our original assumption was changing temperatures. Honestly I need to start writing down the temp and humidity and where the "chicken zero" is at specific times to try to determine what is causing this.
Has anyone else noticed this and have an explanation?
George
George
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- Innocent
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George,
Yes MOA changes with temperature, light, elevation and of course humidity (that can cause mirage). Talk with Tureau next time you see him about locking a rifle in a vice and shooting every 30 mins from sunrise to sunset...and the range of movement of the group.
Mary
Yes MOA changes with temperature, light, elevation and of course humidity (that can cause mirage). Talk with Tureau next time you see him about locking a rifle in a vice and shooting every 30 mins from sunrise to sunset...and the range of movement of the group.
Mary
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- BlauBear
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Sure it does George! I'll look up the reference when I get home and post it, but I know Kitty can fill in the details.
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Light
Not saying it cannot affect POI, just saying I do not believe it affects a scope sighted gun.
But I am willing to learn.
Stay dry,
George
But I am willing to learn.
Stay dry,
George
George
No one cares how much you know until they know how much you care.
No one cares how much you know until they know how much you care.
- BlauBear
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This article is based on open sights, but still has relevent points:
http://www.washingtonbluerifles.com/KeysConsistency.htm
This article is more directly related:
http://www.targetshootingnz.co.nz/uploa ... 2_Pt_5.pdf.
As lighting conditions change variable amounts of light enter your eyes and cause the target to appear brighter or dimmer, light direction changes shadows and sharing... Variations in sunlight are more intense at the Benton range because when that place is bright, it's really, really bright.
http://www.washingtonbluerifles.com/KeysConsistency.htm
This article is more directly related:
http://www.targetshootingnz.co.nz/uploa ... 2_Pt_5.pdf.
As lighting conditions change variable amounts of light enter your eyes and cause the target to appear brighter or dimmer, light direction changes shadows and sharing... Variations in sunlight are more intense at the Benton range because when that place is bright, it's really, really bright.
"If the America people ever allow private banks to control the issuance of their currencies, first by inflation and then by deflation, the banks and corporations that will grow up around them will deprive the people of all their prosperity" - TJ
- deadeyeky
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yup, i see it every time i practice in the afternoons, ill check my chickens zero, and by the time our practice match gets to turkeys(and the temp goes down a little) i hafta come up 1/2 moa or 3/4 moa from my original turkey and ram setting, if i start on turkeys i see the same thing when i get to chickens and pigs, happens to me every week.......
Last edited by deadeyeky on Wed Aug 27, 2008 4:07 pm, edited 1 time in total.
I do my best not to think i know it all, but i do know i know half of what i think i know now, so if i mess something up, cant i get an alibi?
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Yeah, I couldn't disagree more. Changing light does not change POI in any way whatsoever. The fact that some people have problems using their open sights depending on how light is falling on their open sights is completely irrelevant to our shooting silhouette with scopes. There are all kinds of other factors that can affect POI, but lighting most certainly isn't one of them, not for us. Move along.
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As far as the POI changing throughout the day when using aperture sights. Isn`t that a result of the reaction of light on the front postand changing the your point of aim and not the ammunition being used?
Keith
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Right - light doesn't affect ammunition, but it does affect how we see the target by changing light and shadow on the target, and ambient light determines how much light our eyes receive. The effect is much more profound on aperture sights because of light and shadow on the front post or blade but it also affects scoped shooting.Chattcatdaddy wrote:As far as the POI changing throughout the day when using aperture sights. Isn`t that a result of the reaction of light on the front postand changing the your point of aim and not the ammunition being used?
"If the America people ever allow private banks to control the issuance of their currencies, first by inflation and then by deflation, the banks and corporations that will grow up around them will deprive the people of all their prosperity" - TJ
- BlauBear
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Why wouldn't it? It's a matter of how they eyes see and the brain interprets a target. Scopes don't magically compensate for shadow and glare.
"If the America people ever allow private banks to control the issuance of their currencies, first by inflation and then by deflation, the banks and corporations that will grow up around them will deprive the people of all their prosperity" - TJ
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I suggest you go read what you told us to read. They're talking about how the light affects how you see the open sights.
Now, if you actually have problems seeing the targets through a scope as the light changes, well, that's your brain. I have absolutely no problem with it at all. As the light changes from early morning to mid-afternoon, I do not all of a sudden think the rams have shifted an inch. But you go right ahead and change your scope settings! I won't mind!
Now, if you actually have problems seeing the targets through a scope as the light changes, well, that's your brain. I have absolutely no problem with it at all. As the light changes from early morning to mid-afternoon, I do not all of a sudden think the rams have shifted an inch. But you go right ahead and change your scope settings! I won't mind!