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Thread: High scope and canting

  1. #1
    Inactive Member

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    Default High scope and canting

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  2. #2
    Protea FT Team '15
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    That is why we us ethe following:

    http://www.microlevel.biz/cant_errors.html
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  3. #3
    Sharp Shooter

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    The only thing I can see in the graphical explanation is that the effect of gravity and thus the amount of drop has been assumed to be constant regardless of the launch angle.

    It is a fact that the trajectory of a projectile changes with launch angle. In these illustrations the launch angle is determined by the LOS and can thus not be the same in both cases.
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  4. #4
    Sharp Shooter
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    Quote Originally Posted by Rooies View Post
    The only thing I can see in the graphical explanation is that the effect of gravity and thus the amount of drop has been assumed to be constant regardless of the launch angle.

    It is a fact that the trajectory of a projectile changes with launch angle. In these illustrations the launch angle is determined by the LOS and can thus not be the same in both cases.
    Affects of gravity is always the same. Gravity does not change. What you can have is that the pellet induces lift at a more acute angle. and thus gravity may appear to have less effect but it in fact it is constant at a given altitude. Cant is real. Ignore at own peril. In fact I believe cant has a bigger impact on a shooter's self confidence when he cannot figure out why his rifle is missing.

    Facts to consider:
    Cant has less effect the further away your zero is.
    Cant has less effect the closer your LOS is to your bore line.
    From what I have seen, the more unnatural your shooting position is to you the more likely you are to cant and vice versa.
    It is much easier to cant without knowing at a higher magnification as you see less of the surroundings.
    Shoot with a level when ever you can...
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  5. #5
    Sharp Shooter

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    Please read.
    I said the effect of gravity. It is common knowledge that gravity is a constant but the steeper the launch angle of a projectile the greater the effect of gravity since more of the projectiles forward motion is used to overcome gravity. On the other hand if you launch a projectile at an angle below the horizontal the projectiles drop would be greater since it is aided by gravity. Therefore the amount of drop experienced would be different with a positive and negative launch angle. However this phenomenon would be close to unnoticeable in the case of a pellet at 50m but fairly exaggerated at 100m. In the attached diagram it is illustrated that the vertical component of the projectile's momentum either works with or against the gravitational acceleration force.

    I'm aware that this is a moot point since nobody would shoot their rifle upside-down. So for the purpose of the discussion on the effect of canting of a higher or lower mounted scope on POI tilt should be concluded that it is equally bad in both cases and should be avoided at all cost.

    What exactly are the rules regarding the use of scope levels?


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  6. #6
    Sharp Shooter
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    Quote Originally Posted by Rooies View Post
    Please read.
    I said the effect of gravity. It is common knowledge that gravity is a constant but the steeper the launch angle of a projectile the greater the effect of gravity since more of the projectiles forward motion is used to overcome gravity. On the other hand if you launch a projectile at an angle below the horizontal the projectiles drop would be greater since it is aided by gravity. Therefore the amount of drop experienced would be different with a positive and negative launch angle. However this phenomenon would be close to unnoticeable in the case of a pellet at 50m but fairly exaggerated at 100m. In the attached diagram it is illustrated that the vertical component of the projectile's momentum either works with or against the gravitational acceleration force.

    I'm aware that this is a moot point since nobody would shoot their rifle upside-down. So for the purpose of the discussion on the effect of canting of a higher or lower mounted scope on POI tilt should be concluded that it is equally bad in both cases and should be avoided at all cost.

    What exactly are the rules regarding the use of scope levels?
    not the case. You will miss a target if you do not take it into consideration. And the effect is equel if you shoot down or up as gravity acts vertical. in both cases you will need to aim low to hit the target. The reason for this is simple. Less gravity acts on the pellet as you are not traveling perpendicular to the effect of gravity. Thus for the distance the pellet has to travel if you shoot up or down there is only a percentage of gravity acting on the pellet. How much? the percentage the horizontal distance to the target forms from the actual distance...

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  7. #7
    Sharp Shooter
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    Thanks for the link George, very interesting and with the proof of the pudding in pics, even I can now understand it
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  8. #8
    Sharp Shooter

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    The theory holds true (more or less) only if you are shooting at the distance to which the rifle is dailed in.
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  9. #9
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    Read the following articles by Jeroen Hogema

    Scientist and shooter


    1. Air rifle cant experiment

      EFFECT OF CANT ANGLE VARIATION ON POINT-OF-IMPACT IN AIR-RIFLE SHOOTING
      Copyright Jeroen Hogema



    2. Line-of-sight height and the cant angle effect in air-rifle shooting

      LINE-OF-SIGHT HEIGHT AND THE CANT ANGLE EFFECT IN AIR-RIFLE SHOOTING
      Copyright Jeroen Hogema, 5 September 1999



    3. Shooting sport ballistics, ballistiek voor de sportschutter

      Shooting sport ballistics
      Copyright Jeroen Hogema
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  10. #10
    REP: Maestro Design FT Accessories

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    Hi there,

    The pictures on Microlevel website are totally BS, they ain't got a clue how canting errors work. Jeroen does understand this phenomenon.

    Best regards,
    András
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  11. #11
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    Am I wrong in saying that cant error is 'insignificant' inside of a rifle's zero, and accelerated beyond that point?
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  12. #12
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    No, canting error is significant more or less everywhere. Mainly, it depends on the canting angle and the pellet drop, but the aiming method can modify, even neutralize it. Please read my article about the theoretical background and you'll see how this works. The point of this all is that you have to buy a bubble level and can forget canting errors, but some shooters (e.g. HFT) can't do this. The original question was that do high scopes increase canting errors and my answer was that generally not, in a few specific cases can increase but also decrease it.
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  13. #13
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    Practically, if you look at extremes, you are less likely to cant the rifle if you have a high scope. The higher the scope, the less 'correct' a setup would feel with a smaller degree, due to the DISTANCE from vertical.
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  14. #14
    REP: Maestro Design FT Accessories

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    Good point, I 've got a 50 mm high scope rail and I can use it as a reference plane for verticals. But of course the bubble level is the best way to keep the rifle vertical. I had tried an electronic level, too - but it wasn't so sensitive as the bubble and when the battery went flat I was in trouble... Bubble levels are cheap, sensitive and reliable.
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  15. #15
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    I have no time for elecronic levels... they are distracting and gimmicky. A simple bubble level will never let you down.
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