Making your own indoor optical training aid

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Roddy

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I saw a design online for a way to make your own IOTA. For those of you that don't know what that is it's a cover that goes over your objective lens that allows you to focus a scope well below the minimum focus distance, around 11'.

The one I saw just said to cut a circle of plastic to fit over your objective lens then cut a hole in it 1/3 the diameter of the cover. For a 2" lens you should cut a 0.66" hole for example.

I tried it and it worked a bit. Is this something you can do at home? I feel it's only working half as well as it should. One of the ones you can buy has a lens of some sort in the cover.

On a side note when I tried spinning off my sun shield to try this I was actually spinning off my objective lens! I think I almost spun it right off before I realized the sunshade was stuck. I hope I didn't damage anything or let moisture in.
 
bsand said:
what scope did you end up disassembling unexpectedly?
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A Bushnell ERS 3.5-31x. I haven't taken the sunshade off in a while and didn't realize it was stuck. It was really on there. I had to put a rubber strap type filter wrench on the 1/2" wide part that spins off with the lens in it.

I never completely removed the lens so I hope it's okay. Are they purged woth argon gas or something? It was $2100 and I feel pretty stupid.
 
Roddy said:
A Bushnell ERS 3.5-31x. I haven't taken the sunshade off in a while and didn't realize it was stuck. It was really on there. I had to put a rubber strap type filter wrench on the 1/2" wide part that spins off with the lens in it.

I never completely removed the lens so I hope it's okay. Are they purged woth argon gas or something? It was $2100 and I feel pretty stupid.
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Yes, it is purged, not sure if you would have compromised it though. If it starts fogging send it for warranty repair.
 
Well my dumb mistake aside, has anyone made one of these?
DSC00679.jpg
 
I have the IOTA. It definitely makes a big difference and I'm glad I have it for dryfiring, but it's not the same as looking at a 200yd target. Obviously the image is darker with the smaller objective opening. The clarity otherwise is pretty good if you get the EXACT right distance (+/-2", which I normally don't).

I'm just saying don't expect it to look the same as it does on the firing line.
 
Kane519 said:
I have the IOTA. It definitely makes a big difference and I'm glad I have it for dryfiring, but it's not the same as looking at a 200yd target. Obviously the image is darker with the smaller objective opening. The clarity otherwise is pretty good if you get the EXACT right distance (+/-2", which I normally don't).

I'm just saying don't expect it to look the same as it does on the firing line.
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Where did you order it from? Is it something you could make yourself?

And is there any PowerPoint presentations you can download to practice dry firing at?
 
I called Bushnell about loosening the objective lens assembly. They said I could have compromised the scope and reccomend I send it to them. I may wait and see what happens. I don't want to take it off if I don't have to.

Is there a condition that could increase the likelihood of a scope fogging internally? If I could freeze it and then warm it up or something like that and see if it fogs then I would know if it needs repair I was thinking.
 
Roddy said:
I called Bushnell about loosening the objective lens assembly. They said I could have compromised the scope and reccomend I send it to them. I may wait and see what happens. I don't want to take it off if I don't have to.

Is there a condition that could increase the likelihood of a scope fogging internally? If I could freeze it and then warm it up or something like that and see if it fogs then I would know if it needs repair I was thinking.
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Did the inner objective lens retaining ring turn for sure, or just the outer ring? Just wondering as I've turned the outer ring before on scopes and the inner stayed put, may not be the case with your particular scope as in my case it was low end scopes and not higher end as yours, I've never done it on my higher end optics.

Just something you may want to look at before sending it away as it would be hard to see with the sunshade on, maybe give it a turn again with the shade off and see if the inner moves or not.
 
MrSharp said:
Did the inner objective lens retaining ring turn for sure, or just the outer ring? Just wondering as I've turned the outer ring before on scopes and the inner stayed put, may not be the case with your particular scope as in my case it was low end scopes and not higher end as yours, I've never done it on my higher end optics.

Just something you may want to look at before sending it away as it would be hard to see with the sunshade on, maybe give it a turn again with the shade off and see if the inner moves or not.
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Funny you should ask. I held a pencil eraser against the lens and turned it because I couldn't see it with the sunshade on. It was being turned.

I'm hoping it was still sealed as the lens never came all the way off but the technician said it could be compromised. That sucks as the whole point of a nice scope like this is you don't have to worry about that kind of thing.
 
I decided I am going to try to fit the whole rifle in the freezer without the girlfriend knowing and then see if it fogs as my limited research tells me that any moisture will show up as fogging. Perhaps someone with more knowledge can let me know if there is a better way.

I'm still hoping that no argon rushed out and no moisture rushed in while the lens was loose.
 
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Interesting. Might have to give this a try when there's nothing to do in the winter.

Humm, the front ring of my Bushnell scope was unscrewing as well when I was removing the sunshade as well. I didn't remove it entirely, just a few turns before I noticed it rotating along with the sunshade. I should get mine checked.
 
Trinimon said:
Interesting. Might have to give this a try when there's nothing to do in the winter.

Humm, the front ring of my Bushnell scope was unscrewing as well when I was removing the sunshade as well. I didn't remove it entirely, just a few turns before I noticed it rotating along with the sunshade. I should get mine checked.
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I will let you know how mine looks.
 
Roddy said:
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I will let you know how mine looks.
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Kool. I'll test mine when the temp starts hitting the negatives. I'll stick the rifle in the shed for a couple hours and bring it back inside the house and see if it fogs. Still a bit of mid-high teen temps all through next week. Not complaining... :)
 
Roddy said:
Where did you order it from? Is it something you could make yourself?

And is there any PowerPoint presentations you can download to practice dry firing at?
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I got mine from the States, but it sounds like Bob Raymond is the guy to talk to up here now. Can you make it yourself? It's a Butler Creek scope cap with a plastic piece covering probably 70% of the objective lens and a glass lens in the centre. It would be very easy to make, except for the glass len. I'll have to check tonight to see if that lens is just flat glass or if it actually does something.

For a good dryfire target and a powerpoint presentation check out the 6.5 Guys:
http://www.65guys.com/dry-fire-practice-and-the-indoor-optical-training-aid-iota/
 
Do you have any contact information for Bob? I can't find him on google.

After testing my scope appears to be fog free! I hope it stays that way.
 
Got this from the Youtube link.


- THe IOTA can be ordered by contacting Chuck Neller at: chncranes@aol.com
- Chuck can also be contacted through the Snipers Hide forum by private message (PM) where he goes by the screen name of 264shooter
 
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