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FOV, subtensions & thin opening

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Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: June/24/2011 at 12:03
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Optics GrassHopper
Optics GrassHopper


Joined: June/24/2011
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Hi

I have a Leupold M8 4x, regular duplex, mounted on my DW 44mag pistol. I decided to design a target to let me do 25yd accuracy testing.
From their catalog
Heavy - 1.6"
Thin - .5"
Thin Opening - 10.5"
FOV - 9' or 108"
all at 100yds.
 
If you look at the regular duplex through the scope or at a picture in their catalog (I know they're not CAD but they're close) it's obvious to me that the Thin Opening is 1/5 of the FOV, not 1/10 that their specs dictate.
 
I e-mailed Leupold - no response. So I just called tech support. Charlie said he understood my question but he'd have to research and get back to me. And it might take a couple of days.
What am I missing?
tia
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: June/25/2011 at 20:05
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Optics GrassHopper
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Joined: June/24/2011
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The 2011, and the 2008 catalog describe the 'regular duplex' reticle subtensions for this 4x ler/eer pistol scope @ 100 yds as Thick 1.6”, Thin .5” Thin Opening 10.5”, and FOV 9’ or 108". This makes the ‘Thin Opening’ 10% of the vertical FOV. 
Plugging that into Visio and developing a target size/distance prototype ain’t working.
 
Trying to verify the FOV & reticle subtensions and dimensions for their 2011 offering was a start. I could backtrack to my antiquated M8 exact variables later with Leupold.
 
But now this is a bogger Leupold problem.
 
When I talked to Charlie, in tech support, he said artwork in catalogs was not accurate. And I acknowledged it wasn’t CAD. I’m talking about Thin Opening accounting for 20% of the FOV, not 10% as stated. BIG different in reticle ‘sight picture’. He said he needed to get one to ‘see’? it. He said it may take a couple of days to get back to me.
 
This is all @ 100yds
 
 
 
 
                                10%                   &                      20%
 
It's obvious to me that the proper ‘Thin Opening’ is 20% of the horizontal field of view – FOV.
 
Their manual ‘Thin Opening’ 10.5” and FOV 108”  is incoorect. For how long?
 
So I’m guessing they have to change their tables!
 
That’s why I joined here. Given the ‘generic’ specs of this scope & reticle what changes ?
 
FOV - 9’ to 4.5’ ?
Or ‘Thin Opening’ - 10.5” to 21” ?
 
some help please
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: June/26/2011 at 04:53
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Optics Journeyman
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take it to a range and measure it at 100 yards.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: June/26/2011 at 17:10
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Optics GrassHopper
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Yes, had figured that out.
But thought I'd ask experts and save a trip. Then could go out with a prepped target.
Oh well.
 
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: June/28/2011 at 12:49
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I have moved this thread out of the "Member's Review" section to the "Riflescopes" section where it should have been from the beginning.

As far as the original post goes, I would not put much stock into catalog pictures.

If you do not trust the spec numbers (which tend to be correct fairly frequently), go point the scope at something and figure out the field of view and reticle subtensions at some known distance.

ILya
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