DIY IOTA (Indoor Optical Training Aid)

chrisward3

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Ottawa, ON
I've been getting a lot of PMs on how I went about making my own IOTA, so here's the quick and dirty story behind it.

First off, was all set to order the actual IOTA from Chuck in Nevada but since he would only accept USD cash mailed to him, and the price+shipping ($70USD total), I decided to reach out to some local optometrists to see if we could achieve the same results. The first one or two shops played dumb and said they didn't think it was possible, but the third was very interested in solving the problem, and I brought the scope to them, and was in and out in a less than 20mins with my own IOTA.

What you need:

- Butler Creek scope cap (that fits your scope's objective lens)
- +0.25 diopter lens (talk to the optometrist who will get an oversize lens in, which are available in different materials, I went with plastic for $20+$10 labour)
- Electrical Tape (this will be used to tape off part of the lens like a camera's aperture to cut down the amount of light collected into the scope)

Bring the scope (or scope cap) into the optometrist, and he will be able to cut the lens diameter to fit inside the cap.

Once you get home, tape off roughly 2/3 of the lens, leaving only about 1/3 pin hole in the lens (this will not affect your FoV, just the amount of light collected)

This brought my focus range between 10-14ft depending on parallax setting, from the low 10m/30ft setting on my S&B to infinity.

I did notice that my eyes got tired very quickly without the taped-off aperture, and eye strain was significantly reduced with the tape.

Target-wise, I took some PRS match books and scaled the targets (squares, diamonds, circles, IPSC) to a 12ft range. IE...a 12" square at 529m in an actual match, translates to a 2.1mm target at 12ft). I then drew these to scale in Photoshop and set them up as different stages so I could practice transitioning, and dialling/holding and the sight picture would be comparable to the target size in real life through the scope.

Pics below, hope this helps!

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I use the butler creek since it has that lip to sandwich the lens between the scope and the lip. I’m not familiar with the vortex cap, but if it’ll hold the lens (or the lens could be affixed somehow) it should work.

Luckily (I guess) for me, my ocular butler creek crapped out about the same time I had this made, so it was a great excuse to upgrade to tenebraex covers and keep the remaining butler creek for the iota.
 
chrisward3

Mine works great. Thank you again for helping me out to build mine.

I went with the tenebraex and the soft rubber holds the lens and the disc in place. The hole in the disc is 1/3 the
size of the lens. The place I got the lens could not get their machine to measure the inside of the cap to grind the lens to size.
I brought it home and used a belt sander (fine grit) to trim down the plastic lens. Slipped them into place and wow.

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Does it need to be specifically +0.25 diopter? Would say a +1 work?

Thanks

I had been trying to solve this issue on how to make an IOTA for the last bit. Same as Chris, I contacted Chuck but sending cash in the mail didnt sit right with me. I approached it from a photography background, thinking i could make a +1 close up filter work - and it so happened that a 62mm filter with the steel ring around the lens fit perfectly within a cap for my Gen2 Razor. I put one together, wouldnt focus worth a crap at 12ish feet... but I found that it focused at .93m almost perfectly; although it would only allow me to go to about 12X on my scope. Not ideal. I did the math and figured a 0.25 close up filter would be perfect... but they don't make them for camera's that I could find and it had me stumped. Big thanks to Rookie (who got it from Chris) on the tip for the lens from the optometrist. The optometrist I went to was less than enthusiastic about helping me out once I answered why I was looking for such an item, but they brought one in for me anyway. They wouldn't turn it down for me, but I just ended up double-sided taping it to a round piece of plywood with a bolt through the middle, then stuck it in my cordless drill and spun it against some 120 grit sandpaper... turned down from 70mm to 65mm in a few minutes. Instead of electrical tape, I grabbed some limo window tint, doubled it up, and stuck it to the inside of the lens after punching the center hole out with a piece of small steel conduit (OD of 18mm is basically perfect for the 1:3 ratio).

Some photos I had taken while doing it to explain to a friend:
https://imgur.com/a/YhXpH


So to answer your question, a +1 diopter sorta works, but for practical practice for what you want to do with it its not really worth building. The +0.25 diopter is about perfect for a 'realistic' feeling.
 
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Thank's for the tip, I have a USO 525x58mm and I arrive at the same results (11-14') with great clarity

It work so well that I decided to push it further, I printed some 30" wide posters with 2moa targets on them (2moa at 4 yards) to practice dry fire on barricades in my basement


Put numbers on the targets








Scope set at 15x
 
Nice setup with those posters. I've been using the powerpoint file the 6.5guys posted on their blog now, but it has never felt quite 'right'. The posters look awesome.
 
The optometrist I went to was less than enthusiastic about helping me out once I answered why I was looking for such an item, but they brought one in for me anyway.

Ya, the first two I called played dumb and said there was no such thing. The third lab I called, got this older lady who was genuinely curious to see if it was possible, and their optometrist was equally enthused. Her one request is that I just bring the scope, as the rifle might scare some of their clients...lol. The scope is on a QD mount anyway and almost always lives OFF my rifles so it was easy peasey. Not sure why you had issue with them turning down the radius (unless they just didn't have the tool), because mine was just thrown into their lens cutter (which was easier since it was a circle vice a glasses-type shape).
 
If anyone's interested in some movers practice as well, I've uploaded a mp4 file with a mix of stationary 1MOA @ 2MOA targets, as well as a 3 MOA and 4MOA mover (1MOA roughly being 1/16" @ 12'). The sizes are damn near perfect on my 32" monitor. It's posted at: https://drive.google.com/file/d/1fZ64u5ZFWycsa2dCCaHRJLhFumIM-RZd/view?usp=sharing

This is very interesting!
So, you would make up all kinds of different scenes?
So how would it work on say a 16" laptop?

I'm just thinking a laptop would be easier to move around to your "indoor range" ie. the basement or garage.
 
I used PowerPoint to make the movers.. any image file you have could be used as a back ground.

A smaller monitor could be used.. Don't need to have so many different target locations. Would just need to adjust the target size to make sure it still scales to the appropriate size in MOA on whatever display you use.
 
FYI, if you are near London Ontario, Charles at "Crosseyed Optical" can make you an IOTA lens.
They also carry Willey X glasses
 
Nice setup with those posters. I've been using the powerpoint file the 6.5guys posted on their blog now, but it has never felt quite 'right'. The posters look awesome.

I have tried their powerpoint as well. I don't have a copy of MS Powerpoint so downloaded a free viewer. However, it stops part way with an error message.
 
So theoretically, would one IOTA work for all scopes? I have a spare scope with a 50mm bell that I could try bringing to a local optometrist. Could I them swap the IOTA between scopes on different rifles?
 
Yes. As long as you can affix the lens in front of your scope, it will work. It's easiest if all your scopes use the same size butler creek cap, but in a pinch you could just tape the lens itself in front of any scope (as long as center of lens is centered on scope) and it will function.
 
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