Rifle Scopes Kahles SKMR3 Subtensions

[Lexington]

I'm considering a Kahles 624i with SKMR3 reticle. The details of the reticle subtensions are on the Kahles web site, but there is an unmarked dimension I am interested in.

What is the distance between the center of the central dot and the beginning of the horizontal stadia? In other words, what is the size, in mils, of the gap? In the illustration, I added the black lines and used a function to distribute them evenly, revealing that the gap is not 0.10 mils.

It appears to be 0.12 mils.

Help me out. If it's not 0.10 mils, what is it, and why is it irregular?

 

[NotMalware]

It looks like 0.15 mils with some error in your center and maybe some error (tolerance) in the etching and some error in the image. Where did you get the image? How confident are you that it's not distorted?

 

[NotMalware]

Using ImageJ I calibrated the scale on two images of the SKMR3 reticle. The first was from the Kahles web page SKMR3 PDF and the second was your image. I measured 0.13 mils with the Kahles image and 0.14 mils with your image. There is error in the location of the edge due to poor image quality, so the discrepancy is to be expected. The pixuls are pretty large with respect to the edge we're trying to measure. You could get a better measurement with a better image.

 

[Kevin1]

Each of those subtensions is 0.2 mils. Your black lines are each 0.1 mils (half of the Kahles subtensions).

 

[Lexington]

Each of those subtensions is 0.2 mils. Your black lines are each 0.1 mils (half of the Kahles subtensions).

The question is what is the distance between the blue arrows? It's not 0.1 mils and I doubt it's 0.15 mils. I'd like it to be 0.1 mils and think that any other value makes it just a little less convenient to work with.

[IMG2=JSON]{"data-align":"none","data-size":"full","src":"https:\/\/www.ar15.com\/media\/mediaFiles\/30012\/Kahles_SKMR3_defined-320782.jpg"}[/IMG2]

 

[Lexington]

It looks like 0.15 mils with some error in your center and maybe some error (tolerance) in the etching and some error in the image. Where did you get the image? How confident are you that it's not distorted?

I got the image from the Kahles web site. The distance I am looking for is not specified. I want to know what it is.

 

[Kevin1]

It's 0.13 mils.


I took the PDF of the SMKR3 and zoomed it on my screen
http://www.kahles.at/verwaltung/uploads/20170109185159K624i_SKMR3.pdf

I took my caliper and measured the first known subtension. I got 0.231" corresponding to .2 mils
I measured the distance that you were asking and I got 0.155". A little 3rd grade math gave the equivalent of 0.13 mils.

Please let me know if you want me to measure anything else. I have another 45mn to kill before it's wine oclock.

 

[Lexington]

Interesting. Thanks for taking the measurements. It's an unusual measurement (at least I think so). I'd like to hear from the guys who shoot with this scope on a regular basis.

If the gap were 0.1 mils by extending the horizontal line left (and right on the other side), it would be a more consistent reading. "Hold 0.1 mils left" would be easy to do. The eye can divide things in half easily, but half way across is 0.06 mils, and 0.1 mils is kinda sorta close to the stadia line but not quite. The reticle has 0.1 mil graduations between the 3 and 4 mil marks. I think it would be natural to make the gap 0.1 mils for minor holds just off the center.

It was designed this way for a reason. Who knows what it is?

 

[C_R_Slacker]

Ask Shannon kay. He posts in the training and classes forums sometimes. I have a good feeling he will know.

 

[lancetkenyon]

Looks to me by lining up the edges of the .25MIL hashes below/above, that the opening is the same width. Making the gap .125 MIL.

 

[Lexington]

Thanks. I'll accept that the gap is 0.125 mils. The question is why? (or why not 0.1)?

Guys on this forum buy, sell, and trade this scope all the time. Tell me the usefulness of a 0.125 gap. Tell me how it's applied. For all the funky numbers it COULD be, why this one?

(A message has been sent to Shannon Kay.)

 

[C_R_Slacker]

The difference between .125 and .1 is only about an inch at 1000 yards so it's not enough to matter. My guess is he thought keeping the visual balance/symmetry with the .25 hashes was more important .

 

[S.Kay]

You guys need to send me email, I don't get notified when I get messages for some reason.

You guys are right. I spec-ed it even at first but it crowded the dot/center under low light. So we moved it to .15. It is more usable and practical in its design that way. Looking at a reticle on paper vs its actual use is the biggest mistake folks make when designing reticle. That is the biggest design difference of the SKMR and why it is so popular. Under glass it is very practicable and fast, easy to the eye in its usability. That sub tension difference is a non-factor when it is used and the tradeoff weighed more heavily than an a even .1. Hope this helps and if you are in the market for one let me know. I have them in stock.

 

[Lexington]

S.Kay, thanks for answering my questions. The reticle is intriguing and I appreciate knowing something about the thought that went into it.