Please help me understand MOA

Discussion in 'The Basics, Starting Out' started by Nikolakangrga, Dec 20, 2009.

  1. Nikolakangrga

    Nikolakangrga Well-Known Member

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    I believe I have this down but still scratching my head.

    Here is an example:

    My target is ranged at 500 yards.

    My .243 has a -41.6" drop at 500 yards. (200 yard sight it)

    My scope is a VX2 3x9x40

    If I understand this correctly, there are (1/4" adjustments) 4 clicks per ONE moa.

    So if I ranged this target with my RXII Range finder, it would tell me (if all the numbers are correct), that I would have to adjust UP 166 MOA. Is that correct?

    So then I would have to lay there and click 166 clicks so that my crosshairs are dead on with my target?

    Thanks-
    Nick
     
  2. FEENIX

    FEENIX Well-Known Member

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    Yep, 166 clicks x .25 = 41.5 inches. The VX-II's specs shows 56 MOA. You might need a 15 or 20 MOA base to do this but I'm sure the pros will chime in.

    Good luck!
     
    Last edited: Dec 20, 2009

  3. Ridge Runner

    Ridge Runner Well-Known Member

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    nope, not correct

    41.6" at 500 yards is not 41.6 moa it is inches of drop, to convert it to MOA range in hundreds of yards is part of the equasion

    41.6 divided by MOA 1.0473"=39.7 now divide this by range in hundreds of yards
    39.7 divided by 5= 7.94 MOA so 29 clicks of your scope should do it.

    1 moa is 1.0473" at 100 yards
    1 moa is 1.0473" per 100 yards of range so moa at 500 would be
    1.0473 (MOA)x5 (range in hundreds of yards)=5.2365" 1MOA at 500 yards

    each 1/4 MOA click of the scope moves bullet impact .261 at 100 yards at 500 yards each click is
    .261 (moa)x5 (range in hundreds of yards) = 1.305" per 1/4 moa click
    So moa at 822 yards is
    1.0473 (moa) X 8.22 (range in hundreds of yards)= 8.608" moa at 822 yards each 1/4 moa click would move POI 2.152" at 822 yards

    what the scope adjustments do is each MOA changes the angle of your muzzle by about .0069", your crosshairs actualy move down when you dial up, forcing you to raise the muzzle to the correct POA, since your changing the angle of you muzzle it changes the flight of the bullet more the farther the distance.

    MOA= minute of angle, a unit of angular measurement equal to 1/60th of 1°, actualy equals 1.0473" per 100 yards of range,
    so MOA is actualy 2.0496" at 200
    3.142" at 300
    4.19" at 400
    5.24 at 500
    10.473" at 1000 yards
    Hope this helps
    RR
     
    Last edited: Dec 20, 2009
  4. FEENIX

    FEENIX Well-Known Member

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    Cool, that's good to know, I too am new with this (been using BP and B&C) and have the same VX-II scope ... and thanks for the correction/education.

    Ed
     
    Last edited: Dec 20, 2009
  5. KRP

    KRP Well-Known Member

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    29 1/4 MOA "clicks" is only 7.25 MOA. 32 "clicks"(8 MOA) would be much closer to the needed 7.94 adjustment. If the scope actually has 1/4" "clicks" as you state you would need closer to 33 "clicks"(8.25 IPHY). My opinion is you will find it easier to stop thinking in "clicks" and start thinking in MOA(or whatever the adjustments on the scope are).
     
  6. MontanaRifleman

    MontanaRifleman Well-Known Member

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    Plus one... it's easier to stop thinking in clicks and start thinking in MOA. Less counting.

    Another thing... I'm not an expert on Leupy's but some scopes say MOA and are really calibrated to inches per hundred yards (IPHY). You need to know which system you have to get right drop.

    Mark
     
  7. HUAINAMACHERO

    HUAINAMACHERO Well-Known Member

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    Have the same scope. Interesting discussion. I am learning with this thread:)
     
  8. Chas1

    Chas1 Well-Known Member

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    Montanarifleman, it's easier to stop thinking in clicks and start thinking in MOA. Less counting. Help me understand how that's possible irregardless of conversion equations...whether it 29 or 32 don't you still have to count clicks if the scope has 1/4" clicks? Not disputing just trying to understand.:)
     
  9. MontanaRifleman

    MontanaRifleman Well-Known Member

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    Good question and here's how I think about it. If you have to dial up, let's say 8.6 MOA, that equates to 34 clicks. Turrets aren't numbered by clicks but they are numbered by MOA and usually 1/4 increments. In this case the only counting I have to do is 2 clicks past 8. If I'm thinking in clicks, I have to carefully count each click up to 34. Also (and I'm not an expert on all the ballistic software out there, but most software is probably going to give readouts in MOA and not clicks. If it does give it in clicks that's just more redundant info.

    So it's a lot easier for me to just look at the MOA adjustment and dial to that number and dial another couple of clicks.

    Hope that's understandable
     
    Last edited: Dec 20, 2009
  10. KRP

    KRP Well-Known Member

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    The scope has minute(or inch or mil) graduations on the turret. If you need to come up 8 minutes, just turn to the 8 on the turret. A minute is a minute is a minute, regardless of distance, etc.. You do have to keep track as you make full revolutions and do a little math but coming up 21.75 minutes is easier to me than counting out 87 "clicks". Numbers are just pulled out of the air for examples.

    That question was directed at MontanaRifleman and he beat me to it with a little more concise explanation.
     
    Last edited: Dec 20, 2009
  11. Nikolakangrga

    Nikolakangrga Well-Known Member

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    I really appreciate all the help and I am also glad others are benefiting from this post. BUT im still having a hard time understanding how you come up with your final MOA adjustment? Can someone please show the math step by step? I do understand now how to make your MOA adjustments versus counting each "click" thanks to you guys in this post.

    Thanks again,
    Nick
     
  12. Ridge Runner

    Ridge Runner Well-Known Member

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    KRP caught my mistake, How I came up with 7.25 moa is beyond me! now say you would dial in 29 clicks, or 7.25 MOA into the scope and take the shot at 500 yards.
    7.25X1.0473x5= 37.9", you were originaly 41.6" low so POI would be 3.7" low at 500, might not matter but, if you keep everything you can control as close as possible, then your chances of a first round hit are better since your data is right and all you have to worry about is the 12-15 FPS ES of your load, the effect (although minimal, but still there) of humidity, and a couple tenths of an inch of bar pressure, you can't control everything but keep your data as accurate as possible.
    RR
     
  13. Chas1

    Chas1 Well-Known Member

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    So counting moa versus clicks only works if your scope has moa numbers...that I understand and I guess that was in mind when the advice was given to count moa and not clicks but if a scope has no moa numbers and just 1/4" increments then I guess you'd still have to count clicks...correct???
     
  14. Ridge Runner

    Ridge Runner Well-Known Member

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    Niko,
    I'm not real good explaining things but I'll try,

    Lets look at it like this, I'm on my favorite crossing, I've glassed a doe feeding in a clearing at 960 yards, I'm shooting my 7mm Allen Mag, running a 160 accubond at 3575 fps with an actual BC of .62, now all my data is loaded into exbal and it'll tell me how many MOA to set for the shot but I'll try to explain it.


    At 960 yards I am -132.5" from my 300 yard zero, so I take MOA (1.0473) and multiply it by the range in hundreds of yards.
    1.0473x9.6= 10.05" so 1 MOA at 960 yards is 10"so divide 132.5 by MOA at 960 yards and you come up with the final elevation adjustment
    132.5 divided by 10= 13.25 MOA to make zero at 960 yards

    I made a shot once at 1350 yards, I was -360.5" from my 300 yard zero
    1.0473x13.5= 14.1" or round it off to 14" so 14" is 1 MOA at 1350 yards
    360.5 divided by 14" = 25.75 MOA was the final elevation adjustment
    RR