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Thread: Want to try 100M zero, no 100M range...

  1. #1
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    Want to try 100M zero, no 100M range...

    So, I've been reading the stickies on AR zero and want to try the 100m (yd) zero.

    One problem: I'm currently limited to a range that's only 75 yards.

    Any suggestions for how to obtain a decent zero with only access to such a limited facility?

    I know much like the issues regarding the in-accuracy of the alleged "50/200" zero (when zeroed at 50) that there is no substitute for verifying zero at a specific range, but I'm looking for options.

    Thanks

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    I use a 75yd zero for my ARs, just personal preference.

    At 100yds the difference is very small, maybe 1/4".

    Variations in ammo, barrel length, optics/sight height ect.. will also effect it.

    I would just zero at 75yds if I were you, but a 1/4" low at 75yds should be close to a 100yd zero.

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    well you have to work with what you have, you are kinda answering your own question. Do what ever 0 you prefer, I use the 50, then I test at 100 and at 25, using the charts will give me a pretty good idea of where I am at, at 225. They(the charts) were put up because they work. Also if it is that important to me I would find a way to shoot at what ever distance I wanted to be sighted in at, if I needed to drive 3 hours which I did, or more to achieve shooting at 200+ yards then thats what I would do. Also keep a DOPE book and record everything, print out charts and do some good research, there are ways to tell, at least if your on paper at a further distance using a closer 0 sight in.
    Last edited by Blak1508; 04-01-13 at 23:39.


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  4. #4
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    Re: Want to try 100M zero, no 100M range...

    I PM'd Jack, F2S, about this very thing not long ago. Read the Zen if the 100 meter zero sticky if you haven't already. He suggested having POI just under "edit" 1/4 inch below POA at 75 yards. Should get you real close to a 100 meter zero from your available 75 yards. I will be sighting in my M4V7 this way when I find the time.

    Sent from my SCH-I510 using Tapatalk 2
    Last edited by gunrunner505; 04-02-13 at 10:43.

  5. #5
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    I have found this to be quite helpful.

    HTML Code:
    http://m4carbine.net/showthread.php?t=95226

  6. #6
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    Quote Originally Posted by gunrunner505 View Post
    I PM'd Jack, F2S, about this very thing not long ago. Read the Zen if the 100 meter zero sticky if you haven't already. He suggested having POI just under a half inch below POA at 75 yards. Should get you real close to a 100 meter zero from your available 75 yards. I will be sighting in my M4V7 this way when I find the time.
    I must have made a mistake when I quoted you that distance.
    It should be right under 1/4" low at 75 meters.
    Jack Leuba
    Director, Military and Government Sales
    Knight's Armament Company
    jleuba@knightarmco.com

  7. #7
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    Re: Want to try 100M zero, no 100M range...

    Ok thanks. I'll make the changes to my notes.

    1/4 inch low at 75 yards.

    Sent from my SCH-I510 using Tapatalk 2

  8. #8
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    Just for general information on trajectory;

    I really like the web-based JBM Ballistics ballistic calculator.
    Holds good result if you get the input data right and I use it a lot to predict how much effect different variables have on end result.

    http://www.jbmballistics.com/ballist...culators.shtml

    All the info needed (BC, weight, diameter, atmospheric conditions, etc.) can be easily found, but it is always best if you can get real chrono data for your ammo and your gun. The wall of input fields can be daunting, but spending some time with the Google machine will get you enough information to fill in the fields with accurate enough data to be useful.

    Side note: I like to use 2,000 ft for elevation, as it gives good data for Sea Level to 4,000 ft out to 600 meters or so, unless you are going for high precision tasks.
    Jack Leuba
    Director, Military and Government Sales
    Knight's Armament Company
    jleuba@knightarmco.com

  9. #9
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    Wheres the program download, all I got was some toolbar to convert .doc files to .pdf...

  10. #10
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    Quote Originally Posted by N.Franklin View Post
    Wheres the program download, all I got was some toolbar to convert .doc files to .pdf...
    The blue "download" box is just some ad.
    In the body of the page just below the header is a list of several options for perusal.
    I usually use the top one under "General Trajectory Calculators", which is here: http://www.jbmballistics.com/cgi-bin/jbmtraj-5.1.cgi

    Though you can simplify the calculation with the "Trajectory--Simplified", here: http://www.jbmballistics.com/cgi-bin...j_simp-5.1.cgi

    Side note 2: I usually set the temperature for 70 degrees, but temperature really doesn't make much difference unless absolute precision is a necessity or working from extremes.
    Jack Leuba
    Director, Military and Government Sales
    Knight's Armament Company
    jleuba@knightarmco.com

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