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200yd. Zero

Discussion in 'Black Rifle Forum' started by Scamp, Jan 17, 2010.

  1. Scamp

    Scamp Geaux Tigers!

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    I know I have read this before but dang if I can find the thread, anyway...
    My local range has a 100yd limit.
    I am shooting a Colt Match Target Competition 20" 1-9 twist AR. w/ a Leupold Mark 4 6.5-20x50 scope.
    Black Hills 40gr. V-max moly rounds.
    Can I sight it in at a shorter distance and get a 200yd. zero? 25, 50yds??
    Thanks in advance for any help.

    [​IMG]
     
  2. GLOCKMASTER

    GLOCKMASTER Mean Ass

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    The only way to know that you have a true 200 yd zero is to shoot it from 200 yds.
     

  3. RMTactical

    RMTactical Battle Born CLM

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    Same.
     
  4. scottMO

    scottMO Moderator Millennium Member

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    Found this on the net, but different barrel lengths, etc...

    50/200 yard zero -- ballistics
    M4 Carbine (14.5 " BBL) M855 5.56mm ball, 2910 fps muzzle velocity
    Range (yards) 50 yard zero path (inches)
    0 -2.6
    25 -1.16
    50 0.0
    75 +0.87
    100 +1.43
    125 +1.65
    150 +1.52
    175 +1.00
    200 +0.08
    225 -1.29
    250 -3.14
    275 -5.5
    300 -8.41
     
  5. faawrenchbndr

    faawrenchbndr DirtyThirty fan CLM

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    This has worked very well for me for years.
     
  6. W.E.G.

    W.E.G.

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  7. HAIL CAESAR

    HAIL CAESAR Senior Member

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    You'll have to shoot it to be exactly sure. You may find something close but with variables like height over bore, barrel length, different velocities due to lot specific ammo, and different barrel velocities.
     
  8. Sam Spade

    Sam Spade Staff Member Lifetime Member

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    I haven't seen that many samples, but the ones I have seen tell me that the things you mention are smaller differences than the limits of the rifle in question. It's a production rifle shooting factory lots, not a sniper rifle running handloads.

    And topping it, he's got a scope with .5 MOA adjustments; 1 click moves him 1". ETA: Nope, .25MOA. Still moving POI by 1/2" at 200, and his groups are at least double that.

    As always, I'm willing to be corrected.
     
    Last edited: Jan 18, 2010
  9. HAIL CAESAR

    HAIL CAESAR Senior Member

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    If you go by some ballistic chart for your sole source of info and the chart maker used a 26 inch barrel and a very low mounted scope ( scope over bore height) and then the OP uses a 18 inch and a very high scope mount......then that chart ain't worth a hill of beans.
     
  10. CrazyFeet

    CrazyFeet

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    you could check your 25,50 and 75 and compare it to the chart and see how close it is to you. that would give you some idea on how accurate that chart is for you.
     
  11. vafish

    vafish

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    The online ballistic calculators usually have inputs for velocity, Ballistic Coefficient, and height of sights over bore to make the calculations correct.

    But they still are just an estimate and you should sight in at 200 yards if you want to know where your gun really shoots at 200 yards.
     
  12. Alaskapopo

    Alaskapopo NRA ENDOWMENT

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    50 200 yard 0
    [​IMG]

    100 yard 0
    [​IMG]

    25 yard 0
    [​IMG]

    If you have a 100 yard range I would sight in at 50 yards and then correct for windage again at 100 but leave elevation alone. It should be hitting about 2.5 inches high with 55 grain ammo and about 1.5 inches high with 77 grain ammo.
    [​IMG]
    [​IMG]
     
  13. Alaskapopo

    Alaskapopo NRA ENDOWMENT

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