Does this scope reticle look odd?

Joined: May 19th, 2013, 7:18 pm

May 26th, 2017, 7:59 pm #1

Buddy dropped off a Diana 54 in .22. It was suddenly not hitting the target. Naturally I assumed it was a busted scope.

After 200 rounds I am still getting excellent groupings, but here is what I discovered about the scope and necessary holdover reference points:



Does that look normal?
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Joined: February 1st, 2014, 12:51 pm

May 26th, 2017, 8:12 pm #2

At least that reduced the problem for me once, until springer recoil could generate a more permanent solution which prevented any further investigation. X(
Now I shim mounts to keep the reticle close as I can to centered.


The internet gurus all repeat each other "Doesn't happen yada yada...buy another scope."
If we suppose the first statement to be correct, then why buy another?

I'd guess the reticle to be way off center due to mount/swoop/droop ect and changing magnification to induce something like parallax.
(keeping in mind that the phenomenon of shifting poi on variable power is a metaphysical impossibility)




Otherwise I'll be extremely interested to hear someone explain what's REALLY going on, and thank you in advance!



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Joined: January 24th, 2008, 3:00 am

May 26th, 2017, 8:43 pm #3

Buddy dropped off a Diana 54 in .22. It was suddenly not hitting the target. Naturally I assumed it was a busted scope.

After 200 rounds I am still getting excellent groupings, but here is what I discovered about the scope and necessary holdover reference points:



Does that look normal?
If the scope has AO it might be the cause of the change on POI. I've had a
couple of scopes that would not only cause a change in POI vertically but
horizontally too as the AO was adjusted.
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Joined: March 3rd, 2013, 9:49 pm

May 26th, 2017, 8:56 pm #4

At least that reduced the problem for me once, until springer recoil could generate a more permanent solution which prevented any further investigation. X(
Now I shim mounts to keep the reticle close as I can to centered.


The internet gurus all repeat each other "Doesn't happen yada yada...buy another scope."
If we suppose the first statement to be correct, then why buy another?

I'd guess the reticle to be way off center due to mount/swoop/droop ect and changing magnification to induce something like parallax.
(keeping in mind that the phenomenon of shifting poi on variable power is a metaphysical impossibility)




Otherwise I'll be extremely interested to hear someone explain what's REALLY going on, and thank you in advance!


...and the scope is indeed way off center as John mentioned, you can try a set of Burris signature rings or SportsMatch adjustables and dial in your scope at 30 yds with the mounts when the reticle itself is centered. I've used both and really like the Sportsmatch, which allow for vertical adjustment but not horizontal, which you normally shouldn't need much of anyway. Burris allows both, but it's a bit funky with the plastic insert rings but should still work fine. Got the SportsMatch on the new Leshiy with a March 1-8x24 and it's the dog's balls. Good luck.
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Joined: June 4th, 2013, 4:42 am

May 26th, 2017, 9:15 pm #5

Buddy dropped off a Diana 54 in .22. It was suddenly not hitting the target. Naturally I assumed it was a busted scope.

After 200 rounds I am still getting excellent groupings, but here is what I discovered about the scope and necessary holdover reference points:



Does that look normal?
Spitballing some numbers for muzzle velocity and scope height and guessing at the pellet, I would expect the drop at 50 yards to be greater.

It would seem the POA changes when adjusting the objective. If you have a sturdy gun vise, you may be able to confirm by holding the gun (the scope) perfectly still and take note of where the reticle lands on an object downrange at 50 yards, then twist the AO and see if the intersection changes. The object will of course go out of focus when you do that and will be prone to parallax error but if you back your eye away until you see the halo in your field of view, you can use it to keep your eye centered to eliminate the parallax.
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Joined: February 1st, 2014, 12:51 pm

May 26th, 2017, 9:45 pm #6

And a circular POI shift with power change!
I'm not suggesting that's the case here, but clamping the gun up revealed the fault immediately (and made you kinda dizzy looking through it)

Maybe someone could design a variable power that would shift POI as magnification was increased to correspond with bullet drop . Hot damn where do I pre-order?


Jasons post alludes to confounding with simultaneous changes to both mag and objective.
Is that the case?

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Joined: June 4th, 2013, 4:42 am

May 26th, 2017, 9:59 pm #7

the adjustable objective.

The holdover points seem to track correctly with magnification. They are 3 times the amount at 12x as they are at 4x, as expected. Assuming it is a SFP scope, of course.
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Joined: February 1st, 2014, 12:51 pm

May 26th, 2017, 10:32 pm #8

it's a riddle
Hence the lack of pertinent information from an otherwise meticulous individual.

My first guess was actually "combination of off center reticle and focal plane behavior" BUT I've never taken the time to really pin the FFP/SFP mechanisms down, and sound like a dummy often enough without talking outta my bum.



I agree that the magnification appears to function as expected, based on the pic provided.

Not sure if it's possible for the rotation of an properly centered lens (AO) to induce purely vertical optical distortion, other than barrel distortion.
In order for that to happen, the point being viewed (distorted) would need to be somewhere off center in relation to lens.

I also assumed that KW would NOT confound his own investigation by turning all the adjustments at once,
and the distortion would occur after the reticle.


Either way, i would like to hear the explanation for something that supposedly doesn't happen, other than admonishments from the internet for buying a cheap scope...







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Joined: January 1st, 2012, 11:50 pm

May 26th, 2017, 11:26 pm #9

Buddy dropped off a Diana 54 in .22. It was suddenly not hitting the target. Naturally I assumed it was a busted scope.

After 200 rounds I am still getting excellent groupings, but here is what I discovered about the scope and necessary holdover reference points:



Does that look normal?
It's looks about right. The numbers on the magnification ring are usually off a little. I had one cheap scope where they were off by a LOT! They first thing that I do to is verify the magnification. Set a ruler out at 100 feet (measured from the reticle/mag_ring). Set the scope at 12x. The mil-dots should then line up on equal inch increments.

At 10x, the dots line up with each inch at 83'-4".
At 4x, the dots line up at 33'-4".

I've also found that the dot spacing varies slightly with focus.
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Joined: July 25th, 2011, 2:18 pm

May 27th, 2017, 7:23 am #10

Buddy dropped off a Diana 54 in .22. It was suddenly not hitting the target. Naturally I assumed it was a busted scope.

After 200 rounds I am still getting excellent groupings, but here is what I discovered about the scope and necessary holdover reference points:



Does that look normal?
I had a Leapers scope that did the same thing. Zoom in at a fixed distance and point of impact drops. Sent it back to Leapers and they told me there is nothing wrong with it. My wife uses it now to watch the birds in our yard.
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