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Thread: AR-15 Zero Graphics - Various barrel lengths and zero ranges - M193, M855, and Mk262

  1. #11
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    Very useful.

    I've heard some people espousing the benefits of a 37 yard/meter Zero, saying that it gives a good center hit at a wider range that other Zeros. Would it be possible to do the same thing with barrel lengths and a '37 Zero'?

  2. #12
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    Quote Originally Posted by 4thPointOfContact View Post
    Very useful.

    I've heard some people espousing the benefits of a 37 yard/meter Zero, saying that it gives a good center hit at a wider range that other Zeros. Would it be possible to do the same thing with barrel lengths and a '37 Zero'?
    That's pretty much a 300 meter zero, but with no confirmation at actual distance.

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  3. #13
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    Quote Originally Posted by Failure2Stop View Post
    That's pretty much a 300 meter zero, but with no confirmation at actual distance.

    From Tapatalk:
    Jack Leuba
    Knight's Armament Company: Military/Govt Product Liaison
    F2S Consulting: Director of Shooting Stuff
    Confirmation at distance is what so many people forget about. People are really into short distance/rising branch zeros, which is fine beacuse it takes less time. But most people don't realize that it isn't as useful for the windage as it is for elevation. Windage deviations will really show at the far/falling branch end of the zero distance.

    Get on paper close, then go confirm at distance and you will be much better off. Rarely does anyone not have to make adjustments when confirming at the farther distance. This doesn't really apply to the 100m zero as it is quite unique which makes it very useful for certain applications. I am referring to zeroing schemes such as the 25/300m and 50/200m.

    I really appreciate all the time and effort that went into making the graphics in this thread.

  4. #14
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    Thank You!! I will be printing these out and keeping them in my range bag for reference in the future!

  5. #15
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    Quote Originally Posted by Failure2Stop View Post
    That's pretty much a 300 meter zero, but with no confirmation at actual distance.
    Interesting; I'd have expected it to be somewhere between the bullet arcs of zeroing at 25 and 50 yards. Would it be confirmation if I were to zero at 2.5 inches high at 100 yards/meters?

    But you've brought up another conundrum, why is there 'no confirmation at actual distance' when zeroing at 37 meters and putting a group on a target at 50, 100, 200, or 300 meters and there is 'confirmation at actual distance when zeroing at 50, or 100 (or pick your favorite) and putting a group on paper at 50, 100, 200, or 300 meters? Or, am I just misunderstanding what you said?

    I don't really care if the zero range is measured in feet, yards, chains, cubits, meters or even Smoots.
    What I do care about is having the best ability to put a shot center mass at the widest range of .... ranges, neither too high nor too low with just a glowy red dot as my aiming point. If the trajectory never rises more than 3" nor falls more than 3"below POA all the way out to 250 yards I'll be a happy camper. The chances of being engaged by someone past that distance are practically nil, and much less for me as a civilian now.
    Last edited by 4thPointOfContact; 07-15-15 at 23:29.

  6. #16
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    10/10 thread.
    If not me, then who?

  7. #17
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    This is great, really easy way of showing people the difference in zero's especially young joes
    SF

  8. #18
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    Quote Originally Posted by 4thPointOfContact View Post
    Interesting; I'd have expected it to be somewhere between the bullet arcs of zeroing at 25 and 50 yards. Would it be confirmation if I were to zero at 2.5 inches high at 100 yards/meters?

    But you've brought up another conundrum, why is there 'no confirmation at actual distance' when zeroing at 37 meters and putting a group on a target at 50, 100, 200, or 300 meters and there is 'confirmation at actual distance when zeroing at 50, or 100 (or pick your favorite) and putting a group on paper at 50, 100, 200, or 300 meters? Or, am I just misunderstanding what you said?

    I don't really care if the zero range is measured in feet, yards, chains, cubits, meters or even Smoots.
    What I do care about is having the best ability to put a shot center mass at the widest range of .... ranges, neither too high nor too low with just a glowy red dot as my aiming point. If the trajectory never rises more than 3" nor falls more than 3"below POA all the way out to 250 yards I'll be a happy camper. The chances of being engaged by someone past that distance are practically nil, and much less for me as a civilian now.
    "Confirmation at actual distance"

    The trajectory of M193 Ball is such that if it passes through zero at 25 meters, it will pass through zero again at 375 meters. Similarly, M855 will pass through zero at 25 meters and 340 meters. This is why when zeroing on a 1000 inch range (25 meters) you are supposed to set your rear sight on "L" for the M16A1 rear sight or "300/800" with the small aperture (long range) on the M16A2 type sight.

    After you zero at 25 meters, you could 'confirm' that the zero is good at 375 or 340 meters, and this would prove that your ammunition has the muzzle velocity you thought it does, and the bullet has the ballistic coefficient you thought it should.

    For a '37 meter' zero, the 'confirmation range' would be dependent on the Vm and B.C. of the particular load, but for M193 it would be about 375 meters and M855, about 300 meters.

    The reason for the '37 meters' zero:

    With the Army 25 meter zero, the M193 bullet reaches a maximum of +8.5 inches above the line of sight at about 200 meters and drops below -9 inches at 400 meters. M855 goes to 425 meters with similar maximum. The 37 meter zero holds the maximum rise to about 4 inches and the maximum range to the bullet dropping outside an 8 inch circle is about 300 meters, so, out to 300 meters, the 37 meters zero holds the trajectory in half the diameter circle.
    Last edited by lysander; 07-16-15 at 09:44.

  9. #19
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    Great thread. I used excel to create a graph showing the relationship of poi relationship relative to a 4moa reddot, which I've found helpful using that sight at distance as a makeshift bdc.

    Mine is using a 100yd zero and 60gr tap, so it's not directly applicable, but some may find it beneficial to do the same with bbl lengths and ammo discussed here. If you would be interested, someone can pm me the ballistic data for a specific ammo/bbl combo and I could mock one up and add it to the thread.

  10. #20
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    Thanks, for sharing. Great job.
    What can one man do? You never know until you try.

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