GTA
Support Equipment For PCP/HPA/CO2 and springers ,rams => Optics, Range estimation & related subjects => Topic started by: justinp61 on November 29, 2018, 10:41:36 AM
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Thought I'd start another thread rather than derailing mcoulter's thread farther.
I'm 57 (bifocals) and just started shooting some informal 10 meter indoor air rifle matches. We shoot off a bench and off hand, the bench match uses a NRA AR-5/10 10m air rifle target and the off hand uses (most of the time) a NRA B-40/4 10m pistol target. Currently I have two 300S's and have a 601 on the way, all three rifles have their factory FWB sights. I have a set of front aperture inserts from Champions Choice but need one larger than the 4.0 for the pistol target.
There re a couple things I'm not clear on. Does the Gehmann rear iris with the diopter lens just clear up the front sight? Does the AOS clear up the front sight and the target at 10M? I shoot without glasses and currently with my vision the front sight is clear as a bell but the target is out of focus. Is that the way it's supposed to be? Do I just need an adjustable rear iris?
I apologize if these questions are rudimentary but I've only been shooting airguns for about a year and a half and target rifles for six months so I have tons to learn.
Thanks, Justin
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You’ve actually described the basic situation that the AOS is designed for. But I still would not buy that first; the adjustable iris is the vital first upgrade for any aperture sight.
If you are shooting with the OEM eye disks, those probably have a fixed opening between 1.0 and 1.2 mm. That’s actually a good size for maximizing depth-of-field with good lighting; an adjustable iris may not change that much (the adjustment range on the basic Gehmann 510 is 0.8 to 3.0 mm IIRC). That being said…most serious 10-meter guys still use an adjustable iris to optimize their sight picture on the range. The adjustment is “stepless” so allows extremely fine incremental changes.
FWIW: with a non-magnifying iris, I do better keeping both front sight and target in focus with my glasses on.
Where the adjustable iris really shines, though, is outside the well-lit target range. A 1 mm opening is just too small for most field use against any kind of dark or varied background.
The 1.5x lens will of course magnify the whole sight picture slightly, and give you a clearer view of both sight and target. It has a large focus adjustment range (great if ditching your glasses), but the setup still depends on the iris opening size for optimum depth-of-field. Sometimes it takes a bit of fiddling-around time to get things optimized.
If your budget and the range rules allow, you won’t regret getting a lensed unit like the Gehmann 530. Also, the irises are modular in constrution. You can buy the lens as a separate add-on for a plain iris; or remove it from a lensed iris and replace with a plain extension, but these do require some fiddly work with the iris's tools.
Some shooters find that colored filters are a help. They can adjust the contrast between bull and background to be less tiring to the eye. Gehmann makes irises with a built-in rotating filter ring having six different colors, but you can add them inexpensively with a push-on external filter set that they offer.
Again, I’d absolutely start with the adjustable iris, then think about the other bits as you gain experience and see the need.
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Thanks MDriskill.
A buddy of mine loaned me his Gehmann 510 to try, I just haven't put it on yet. Also I have found what is described as a Gehmann 530 for $90. in the poor photo the owner sent the adjuster ring for the diopter is different than the current production 530, he seems to think it's an older model.
I've tried shooting with my glasses, the target is clear but the front sight is not.
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Great that you can try it out for free! Will be interested to see how it goes.
The older magnifying Gehmann models do have a lens section which is smaller in diameter than the main iris. I also has less of a focus range, if that matters; +/- 3.5 diopters instead of 4.5. IMHO the optics are a bit better in the newer ones. You might enjoy a look at Gehmann’s full range...it’s rather amazing!
https://gehmann.com/english/company.php
And note that Gehmann is not the only maker of irises, etc. Centra and AHG Anschutz have an excellent range of goodies as well.
I’ve picked up some older irises used for good prices, but seems like when guys sell the newer ones they don’t take much off the new price!
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Special thanks to both Mike and Justin for all this information. I'm learning a lot! I know so little that I do not even know what I don't know. :-[
You guys are helping me to understand. Boy, I had no idea that peep sights were so complicated.
Is the Gehmann 530 approved for international competition? Even though all my "matches" will be in the basement, I want to play by the rules. ;)
Justin let us know how it goes....
Thanks again,
-Yogi
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Yogi, magnifying sights are not allowed in most formal airgun competitions, not even the puny 1.5X of the 530.
BUT...the good news is, Gehmann has a brand new iris which has a focusing lens with NO magnification. This would correct for most vision problems, but still allow you to shoot legally without glasses. Don't know where you'd find one in the US at the moment though.
https://www.gehmann.com/english/products.php?id=1695&kategorie=20 (https://www.gehmann.com/english/products.php?id=1695&kategorie=20)
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It's pricey.
http://www.champchoice.com/store/Main.aspx?p=ItemDetailOptions&item=5300X (http://www.champchoice.com/store/Main.aspx?p=ItemDetailOptions&item=5300X)
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Yiks :o :o :o :o :o :o :o
That is pricy.....
Thanks again for ALL the information.
-Y
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Hi guys - I knew it would only be a matter of time before the guilt of hijacking became overwhelming, and I thank you Justin for starting this.
Mike very thoroughly said all that I was thinking about posting this morning over my coffee and laptop.
I have a set of front aperture inserts from Champions Choice but need one larger than the 4.0 for the pistol target.
Are you using a clear aperture with the black ring? If so, let me know the OD of the insert. I'm currently in the process of making some, and I just might have the correct OD blank to work with. If not, I can order some. (That's right Mike, I still haven't placed that order ???). I can make one of any size center hole that you need (well, pretty close depending on what tap drill size is closest) and also in colors. I can make the black ring a certain thickness as well, or, without the black ring. Let me know what you're currently using if you're interested.
Here's one I made for my Baikal. It appears non-concentric because of the slight angle I took the pic from.
(http://i663.photobucket.com/albums/uu359/Panzer_2002/20180830_172643_resized.jpg)
Here's another experiment with a center dot. The dot needs to be colored in black.
(http://i663.photobucket.com/albums/uu359/Panzer_2002/20180831_164144_resized.jpg)
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CRIKEY! That is very spendy indeed! I had no idea...must be some serious optical wizardry required to make the no-mag focusing lens work. The “normal” magnifying 530 is a fraction of that price.
I did not know CC carried that one, thanks for the link.
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One thing I wish I had had the foresight to think of was to order the 577 adapter for $9.50. Then I could use the 530 either as it is, or as a 510. Now I have to think of something else I need from them to justify the shipping cost.
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Gehmann has the 0.0x diopter separately, but I'm not finding a price for it anywhere.
https://gehmann.com/english/products.php?id=1639
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Gehmann has the 0.0x diopter separately, but I'm not finding a price for it anywhere.
https://gehmann.com/english/products.php?id=1639
Another dumb question, sorry thanks for bearing with me; Does something screw into the end that is closest to your eye?
-Y
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There are no dumb questions.
That is the "back half" of the 530 setup, or, in the case of this 0.0x diopter, the back half of the 530-0 for $330.00.
That would be the part that one would remove and replace with an adapter (the 577 I referred to above) to make it a 510.
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This is the same thing, but in 1.5x as on the 530. If you could find this part by itself (meaning a place to purchase it) and add it to a 510, the assembly would then be a 530.
https://gehmann.com/english/products.php?id=1225&kategorie=20
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Yogi
Like Stinger said, what you see in that link is only the lens, which screws into the sight. What you don’t see is the iris which you look through, which screws onto the lens.
I would call the lens the “front half” of the assembly instead of the back half though! ;D In the sense that it goes closer to the muzzle.
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I would call the lens the front part of the assembly instead of the back though! ;D In the sense that it goes closer to the muzzle.
I stand corrected. Sorry about that.
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This is very confusing and it took me some time to figure it out myself. Don't know if this pic helps, but I'll give it a try.
9.5x1mm is the thread end that goes into the sight itself. The unknown thread goes into the "front (now ;))" of the iris. This is the adapter I wish I had bought. Now, imagine that the center part of this adapter is actually the body of the "lens", either 0.0x or 1.5x, as in the lower pic. The unknown thread part is what you're looking at and asked what screws onto it.
Their comment that "Allows 1.5x irises" is misleading - should say "Allows the 530 iris"
(http://i663.photobucket.com/albums/uu359/Panzer_2002/577.jpg)
(http://i663.photobucket.com/albums/uu359/Panzer_2002/50309.jpg)
I probably just made things worse.
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So If you install the 50300-0 Gehmann diopter 0.0x, you still need to purchase an iris? :-[
-Y
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That is correct. But I don't know where you can buy it separately anyway.
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That is correct. But I don't know where you can buy it separately anyway.
e bay, it's pricey too.
https://www.ebay.com/itm/50300-0-Gehmann-diopter-0-0x-diopter-correction-WITHOUT-magnification-/372273578687?hash=item56ad3c02bf (https://www.ebay.com/itm/50300-0-Gehmann-diopter-0-0x-diopter-correction-WITHOUT-magnification-/372273578687?hash=item56ad3c02bf)
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Special thanks to both Mike and Justin for all this information. I'm learning a lot! I know so little that I do not even know what I don't know. :-[
You guys are helping me to understand. Boy, I had no idea that peep sights were so complicated.
Is the Gehmann 530 approved for international competition? Even though all my "matches" will be in the basement, I want to play by the rules. ;)
Justin let us know how it goes....
Thanks again,
-Yogi
Guys I shot with the Gehmann 510 last night and have to say I like it a lot better than the fixed iris. I adjusted it to there was no halo effect around the front sight. I sighted in off a bench on a 12 bull NRA 10M air rifle target, after sighting in on the two bulls for that purpose I shot the 10 remaining clean. This the first time I've cleaned one. After that I shot a round of 10M off hand using NRA 10M pistol targets. I shot 478 out of 500, again a best for me. These scores probably aren't impressive to experienced shooters but I'm just starting out and trying to learn and improve as I go.
Thanks, Justin
BTW, my factory iris measured about 1.07 mm and the 510 wound up at about 1.5 mm.