GTA
Support Equipment For PCP/HPA/CO2 and springers ,rams => Optics, Range estimation & related subjects => Topic started by: Norm_m on July 03, 2015, 11:55:42 AM
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OK am I looking at this backwards???
Most scopes have a 1/4 MOA adjustment at 100 yrds. So in my mind that works out as 1/4" at 100 yards, 1/8" at 50 and 1/16" at 25 yards.
Is this correct?
No matter which of my scopes I use that has a 1/4 MOA adjustment at 100 yrds I get more like 1/4" at 100, 1/2" at 50 and 3/4" at 25 yards, just the opposite of what I expect.
When I am shooting at 30 yards on the GTA's 30 yard Rested Target Match and try to fine tune the scope I get the following results. If my POI is on the edge of the 10 ring and I move the turret 1 click, be it elevation or windage the POI moves all the way to the opposite side of the 10 ring. Sure does make it difficult to hit dead center and get more Xs.
This happens with all my Hawke Sidewinders, Bushnells, Weaver and Centerpoint scopes. After talking to Hawke's CS person he said send it in and he will check it out. Well it came back and I was told there is nothing wrong with it and that it worked flawlessly.
This is so irritating that I decided to see if other people have this issue
Norm
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Can't say that about my Bushnell .1mil or swfa ss 1/4moa. My Bushnell FFp moves .1 mil at any and all distances. The swfa ss requires more clicks to move 1 inch @ 10yds than 1 inch @ 100 yds. If I read your post correctly, your clicks get larger as distances decreases requiring less clicks to zero at short distances. I agree with your math, but can't explain your results.
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OK am I looking at this backwards???
Most scopes have a 1/4 MOA adjustment at 100 yrds. So in my mind that works out as 1/4" at 100 yards, 1/8" at 50 and 1/16" at 25 yards.
Is this correct?
No matter which of my scopes I use that has a 1/4 MOA adjustment at 100 yrds I get more like 1/4" at 100, 1/2" at 50 and 3/4" at 25 yards, just the opposite of what I expect.
When I am shooting at 30 yards on the GTA's 30 yard Rested Target Match and try to fine tune the scope I get the following results. If my POI is on the edge of the 10 ring and I move the turret 1 click, be it elevation or windage the POI moves all the way to the opposite side of the 10 ring. Sure does make it difficult to hit dead center and get more Xs.
This happens with all my Hawke Sidewinders, Bushnells, Weaver and Centerpoint scopes. After talking to Hawke's CS person he said send it in and he will check it out. Well it came back and I was told there is nothing wrong with it and that it worked flawlessly.
This is so irritating that I decided to see if other people have this issue
Norm
I've had similar results but I really don't know why. From years ago with a Bushnell Trophy scope when playing with a 12fpe tune.......
(http://www.snapagogo.com/uploads/source/2662014/1411589129_218966792_R9oringsealed11yds.jpg) (http://www.snapagogo.com/photo.php?id=58086)Uploaded at Snapagogo.com (http://"http://www.snapagogo.com")
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Are you keeping same power setting at all distances? If not this could be the problem.
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On my new AA HFT 500 FT I installed a reg so there is no or hardly any difference from shot to shot. At 30 yards if I do my part it will shot one ragged hole all day long. I believe the HFT is capable of one hole groups at 30 yards but the guy holding the gun is not that good.
At the longer distances adjusting the turrets for elevation or windage is acceptable but at 25 -30 yards 1 click and the POI will go from one side of a 1/4" 10 ring all the way to the opposite side and it has jumped over the center X. It is very frustrating as I know I should be able to move the POI at close range a tiny bit with each click.
Norm
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Lock your rifle into rigid gun vice, and verify the results. Otherwise that scope is bad.?...?
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Lock your rifle into rigid gun vice, and verify the results. Otherwise that scope is bad.?...?
My thought as well. Not sure what else it could possibly be.
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I suggest you try adjusting your scope 20-30 MOA down, so your shots aren't hitting the bulls. And then repeat experiment.
Obviously, make sure your scope hairs are aligned vertically. And make sure your objective is focused for the distance you are shooting to avoid parallax errors.
Also, it may help to hold the bulls in the corner of the hairs in one of the quadrants, rather than trying to hold it directly under the crosshairs.
I bet you are having optical illusion issues and/or user bias and/or parallax issues. Because your initial impression is correct. There's no way the scope clicks could work any other way. At 10 yards it would take 10 clicks to move POI a quarter inch.
Regarding parallax error or lens abberations, when you adjust, say, 10 clicks to the right, are you not moving the hairs a little to the left and leaving the optics alone? When you center the hairs in the scope, you're now using a slightly different part of the glass, maybe? I dunno.
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Try different target distances. Turrets may have worn out, if they're only used at this distance, and have lots use on them.
One other important procedure is always turn the turret in the same direction to make corrections. If you go too far, turn the turret back past the mark and then turn the same direction you started from. Turning back and forth allows slack/slop in the turrets to cause issues.
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Thanks everyone for the suggestions.
The turrets are not worn out as I've only had the scope for about 2 -3 months. I always optically center any new scope before I mount it. I us use some of the best adjustable scope rings out there, Sportsmatch adjustable for elevation & windage. The scope is adjusted using the adjustments on the rings so that when finished I am less then 10 click in either direction from optical center. So there is absolutely no extreme spring tension on the internal tube.
I did get one suggestion that seemed to help and will know better when I try it more. The suggestion was once an adjustment is made do not touch it for 20 or so shots giving it time to settle in.
I never have any issues from 50 - 200 yards with any of the dozen or so AG / PBs but from 50 yards in does not matter if it is one of my Discos or one of my ARs that all have scopes mounted and all do the same. I've sent scopes in to be tested and always get the same results "all is fine, works perfect"!
I'm going to see if I can come up with a gun vise to hold my AA HFT rock solid and see what it does. It has to be something I am doing and whatever it is I'm doing it pretty good to get the same results with a variety of guns.
Norm