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Shifting impact point

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Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: December/15/2006 at 07:47
Dolphin View Drop Down
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I have had 3 rifle scopes lately exhibit shifting impact points with change in magnification.  2 were Nikko Stirlings, one made in Japan and the other an Eliter 4200.  When I would go from around 9x to max setting, various for the different scopes, the impact point varied from about 2 inches for the Elite to 4 inches for the Nikko Stirlings.  I usually do not check for this, as I leave it on the high setting and sight on the scope and sight it in and leave it be for hunting.  But in these cases, for some reason I must have been in a hurry and did not look and all were on about 9x and sighted them in with the proper AO adjustment.  So, just for the heck of it, I dialed up the magnification, all were very clear and walla, different impact points, consistently with cold barrels.  Anyone else experience this problem.  I could understand it with the Nikkos, but the Elite, I was a little disappointed.  Everything is mounted properly and tight and returns to the same spot at 9x.  None of them will be a big problem for shooting out to 300 yards based on the change of impact, although obviously the 4 inch change would become more of a problem and 2 inchs could, depending on how well I shoot.  Any opinions on their scopes?

Addendum:  The Nikkos went up to 18x and the Elite up to 16x.

Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: December/15/2006 at 08:10
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This at 100 yards? or 300 yards?

 

J

Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: December/15/2006 at 19:06
Dolphin View Drop Down
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At 100 yards.  Actually it was not an Elite, but a Mueller Eraticator 8.5x25 50mm AO.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: December/21/2006 at 16:13
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That is the standard problem with second focus plane scopes and more scopes than you would think of have this problem.

 

Regards Technika

Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: December/21/2006 at 17:51
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Dolphin have you tried any front focal scopes? There are some very nice discountinued Kahles C FFP scopes floating around at exellent prices and would make a exellent combo with your best Weatherby.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: December/22/2006 at 13:42
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Originally posted by Dolphin Dolphin wrote:

 When I would go from around 9x to max setting, various for the different scopes, the impact point varied from about 2 inches for the Elite to 4 inches for the Nikko Stirlings. 

...None of them will be a big problem for shooting out to 300 yards based on the change of impact, although obviously the 4 inch change would become more of a problem and 2 inchs could, depending on how well I shoot. 

 

Dolphin, if you saw a 4 inch POI shift @ 100 yards, you most definitely will have a problem at the 300 yard mark.  In fact, you may have a problem at 150 yards, depending on the animal you'll be shooting at.  Before factoring in any human error, a 4" change @ 100 means 12" error at 300 minimum, best case.  This means either a miss if you're lucky, or possibly wounding an animal if you're not.  If you have that much shift due to changing the power, and you're certain that's the cause and not loose mounts, bedding, etc., I'd send the scope back and/or replace it.

 

Good luck!

Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: December/22/2006 at 13:52
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IMO it is the Mueller(overrated). I am pretty confident that Dolphin has good mounting skills.

Edited by SVD666
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: December/26/2006 at 19:20
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Originally posted by RifleDude RifleDude wrote:

Originally posted by Dolphin Dolphin wrote:

 When I would go from around 9x to max setting, various for the different scopes, the impact point varied from about 2 inches for the Elite to 4 inches for the Nikko Stirlings. 

...None of them will be a big problem for shooting out to 300 yards based on the change of impact, although obviously the 4 inch change would become more of a problem and 2 inchs could, depending on how well I shoot. 

 

Dolphin, if you saw a 4 inch POI shift @ 100 yards, you most definitely will have a problem at the 300 yard mark.  In fact, you may have a problem at 150 yards, depending on the animal you'll be shooting at.  Before factoring in any human error, a 4" change @ 100 means 12" error at 300 minimum, best case.  This means either a miss if you're lucky, or possibly wounding an animal if you're not.  If you have that much shift due to changing the power, and you're certain that's the cause and not loose mounts, bedding, etc., I'd send the scope back and/or replace it.

 

Good luck!

I mispoke, the 2 inch inpact difference at 200 yards is obviously 4 inches, still withing the 6 inch kill zone, based on how off the impact was on my target and at 300 yards would be 6 inches a could be a problem.  The other scope, definately a problem.  I was really curious as to whether anyone else has tried testing there more expensive scopes to see if they getting any degree at all of a shifting impact point?
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: December/26/2006 at 19:57
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This can be done simply with one of the rigid mounting "sleds" by changing anything in the scope mechanics and watching for crosshair movement. Im trying to make a rigid mounted pipe to mount scopes on to check things like that, also to look for changing "0" from recoil. Incidently, indulged myself, and sold the last born, got a Meopta 3-10x 50 for the Savage muzzle loader, and 2 grouping seems to have stopped.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: December/26/2006 at 22:12
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    I hate to say this but you DO get what you pay for in a scope.Years ago I stopped buying "economy" scopes of ANY brand as invariably I'd found various things wrong with them during use...IE, shifting POI, failure to hold zero, fuzzy images when dialed up, imprecise clicks,fuzzy reticles, distorted edge images.I have learned to simply wait and save for better optics than say " ahh, should be ok for this rifle".As soon as I hear that a scope is "a great deal considering the price" I already know the outcome...it's something else I have to try and sell on Ebay for maybe half what I paid for it....
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: December/27/2006 at 06:30
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I have tried it on any of my expensive scopes.  The only reason I know it happened, as I stated in the initial post, is that I started at the max. mag. and dialed it down later in the shooting session.  Usually I sight in a rifle, leave it alone and go hunting.  Not much of a paper puncher.  I may play around at different ranges, but have never had problems, but never changed my magnification, which was usually on max., 9x.
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