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Discussion Starter · #1 ·
Got this in the mail today. Really looking forward to trying it out.
Big thanks to Art at Shootingsight for spending some phone time with me to properly pair up a new Rx and sight. If you haven’t tried his metal business card with a ton of aperture sizes, you should.




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I have been using Art's rectangular sight for a a few years now. Allows better focus like a smaller round, but less blur on the top of the front sight without creating a dark sight picture that an extremely small aperture would.

I'm also using a +diopter insert to help with front sight focus as my eyes have aged.
 

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Discussion Starter · #5 ·
Good to hear that others have had some success with this. I opted for customized prescription glasses vs the lens insert.
 

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There are two aspects to getting a proper sight picture: 1) getting your relaxed focus in the right place via lens power, and 2) getting the largest possible depth of field around that focal point. Depth of field is a measure of how quickly things go out of focus if they are not at your perfect focal point, said another way: how blurry are your sight and target when you are not focused on either, but on a point in between the two.

Based on the distance to the front sight of an M14, the correct hyperfocal distance calls for a +0.50 diopter added to whatever distance prescription you use.

For depth of field, smaller is better, limited only by the amount of light coming in - which is the open area of the aperture. Most people find that a 0.040 or 0.042 is about as small as they want to go, so about 0.00125 square inches. My patented rectangular aperture is based on two findings: first is that depth of field is axial. vertical blur in an image is determined by the vertical size of the aperture. Horizontal blur is driven by the width of the aperture. We think of round apertures because our pupils are round. The second discovery is that for shooting a front post, horizontal focus is not as important as vertical focus. You have two vertical edges to the front sight, so even if they are blurry, and even if your focus drifts, you can still see the symmetry of if the bull is centered left-right. However for vertical, there is only one top horizontal edge, so if your focus drifts, the width of the blur line shifts, and your front sight looks taller/shorter. So you NEED good vertical focus. You do not need good horizontal focus.

Given that people want about 0.00125 square inches of open area, I decided to take the 0.040 round aperture and make it smaller top/bottom, so you have a 0.025 or 0.027 vertical opening, and then make it oversized left/right, to preserve the open area and brightness. So I am robbing Peter to pay Paul. I am improving focus on the more important top horizontal edge of the post by giving up on some of the less critical horizontal focus.

Testing with one of the military rifle teams, where they took 20 shots, then I replaced their sight and they took 20 more suggested that I did not give up anything in horizontal group size, but gained about 0.25 MOA in vertical dispersion. So not a huge benefit, but a real and measurable one.
 

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Discussion Starter · #8 ·
Still waiting on my new glasses with the modified Rx but I couldn’t wait to give it a try. It was very dark this afternoon with heavy overcast but I figured it would be a good opportunity to see if I could see the target and post in the worst conditions. I shot a rapid sitting string that was a little high but still a 99. I finished with 10 in slow prone and it was getting really dark and I did struggle a little, but frankly I think anybody would have struggled. All apologies for the 9...I’ll own that one:).

Both shot at 200. Looking forward to trying it in good conditions with the right glasses.
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I’ve been using the rectangular aperture for a while now and I generally prefer it. Made master with it and shot a 771 this year.
Also shot a 196 on a MR52 this year with it as well


I switched my A2 to the rectangular as well this year and shot a match with it the day before the EIC. Did not like it and had problems settling down with it. That night I switched back to round and got 6 points the next day
 

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You fix astigmatism with a lens. What you would do is get a hood, then I can make a 3/8" diameter pill lens that has your astigmatism correction in it, that inserts in the hood.

You can fix astigmatism with a slit, called a stenopaeic slit, but then you lose the aperture benefit on the rifle.

For scopes what I reccommend is making a lens the same diameter as the scope eyepiece, and after you orient your astignatism axis, just hold it on with a few wraps of electrical tape. All scopes will vary sphere power by twisting the eyepiece. Scopes do not vary cylinder power, which is what you need for astigmatism correction.
 

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You fix astigmatism with a lens. What you would do is get a hood, then I can make a 3/8" diameter pill lens that has your astigmatism correction in it, that inserts in the hood.

You can fix astigmatism with a slit, called a stenopaeic slit, but then you lose the aperture benefit on the rifle.

For scopes what I reccommend is making a lens the same diameter as the scope eyepiece, and after you orient your astignatism axis, just hold it on with a few wraps of electrical tape. All scopes will vary sphere power by twisting the eyepiece. Scopes do not vary cylinder power, which is what you need for astigmatism correction.
The correction lens sounds great. I haven't had an exam in a while, but I was going to get one done here pretty soon. I'll PM you for details
 

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Discussion Starter · #13 ·
Finally received the glasses with the new Rx. Yesterday afternoon cleared up and made for good testing conditions. I decided to wait until very late in the day with the hope of shooting in very good light, followed by pretty dark conditions when the sun dipped below the horizon. It’s winter in the PNW so the light drops very fast at sunset....and early.

I was using E targets, but I hung a new face on it. The first 10 shots were all X’s and all 10 shots were in full sun. The last 6 shots were right as the light was beginning to drop and the target got a little fuzzier.
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I waited a few minutes after sunset until the light conditions were similar to very heavy overcast, which definitely made the target harder to see. I think the results showed, but sill 100-5X.
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Overall, the lens and aperture absolutely work to make the front sight pop. My distance vision is still pretty good so I’m used to seeing a pretty good target, but straining on the post. I’ll need to train my brain to work with the slightly fuzzier target, especially in offhand.
 
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Optical physics theory, technical testing, and practical testing have all shown that for a front post, a rectangular aperture is better. I patented this maybe 10 years ago. Problem was that CMP disallowed it, even though the written rules did not, then shortly after the CMP finally allowed it, scopes were allowed, so the interest in iron sights died. If I had had this idea 20 years earlier, I would have been rich and famous with gorgeous women hanging on me just to hear me talk about apertures. Not that kind! Get your mind out of the gutter.
 
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