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Thread: Effect of projectile velocity on accuracy

  1. #1 Effect of projectile velocity on accuracy 
    Moderator Moderator AlexP's Avatar
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    Recently I've gotten into airsoft guns, guns that shoot little plastic BBs (don't worry, they won't kill anyone), and I've come up with a question while looking to purchase one. For a projectile shot from a gun, will it tend to be more accurate if fired at a greater velocity, or does velocity not have an effect on accuracy? At greater velocities a projectile will have more momentum, so will greater momentum tend to keep it on a more straight-line path?


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  3. #2 Re: Effect of projectile velocity on accuracy 
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    Quote Originally Posted by Chemboy
    Recently I've gotten into airsoft guns, guns that shoot little plastic BBs (don't worry, they won't kill anyone), and I've come up with a question while looking to purchase one. For a projectile shot from a gun, will it tend to be more accurate if fired at a greater velocity, or does velocity not have an effect on accuracy? At greater velocities a projectile will have more momentum, so will greater momentum tend to keep it on a more straight-line path?
    So much depends on the gun and design. I have had all different kinds of guns. And there was not really a correlation between velocity and accuracy within each guns own design range.

    The most accurate gun I ever fired was a rifled slug, that was spun up in the cartridge. The gun had a recoiling barrel, and smooth bore. It fired totally silent. And you could actually put the rounds through the same hole on the target. It was a Tundra gun. So you could fire it and not scare everything away for twenty miles.

    I could never be that accurate with other rounds at any velocity.

    Sincerely,


    William McCormick


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  4. #3  
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    Greater momentum will not help keep it in a straight line path, except that it will have a flatter trajectory. The air resistance plays a big part in deflecting the projectile from its path, and that increases with velocity.
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  5. #4  
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    A high-velocity projectile ought to be far more accurate than a low-velocity one. The sooner the bullet reaches its target, the less time there is for it to be affected by wind and random air currents.

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  6. #5  
    Administrator KALSTER's Avatar
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    Higher speed would mean a higher axial rotation speed - more accuracy. BB's though are spherical and would behave like gholf balls, i.e. the faster spin the more deviation, as forward momentum decreases as it is turned into rotational- and sideways momemtum. So spherical BB's are less accurate than the hamburger bun-shaped ones. IMO
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  7. #6  
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    Neglecting air resistance, velocity is not related to accuracy in any way.

    But air resistance is proportional to the square of object speed and may decrease the range and height of the projectile. Moreover, to ensure greater accuracy, make sure the plastic bullets are perfectly spherical, since, Bernoulli's effect may cause them to swing randomly in mid-air further decreasing accuracy.
    Beyond Equations,

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  8. #7  
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    Hey there, I've been Airsofting for about a year and a half now, generally the velocity of these things will only determine its range. If you want an accurate on it will need a hop-up unit in it. The hop up unit puts spin on the BB giving it greater accurately for only a slight drop in FPS.
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  9. #8  
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    The hop up unit puts spin on the BB giving it greater accurately for only a slight drop in FPS.
    How is the axis of this spin orientated, parallel to the direction of travel I guess?
    Disclaimer: I do not declare myself to be an expert on ANY subject. If I state something as fact that is obviously wrong, please don't hesitate to correct me. I welcome such corrections in an attempt to be as truthful and accurate as possible.

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  10. #9  
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    There is a rubber part on the top of the barrel which causes momentary friction on the top of the BB. This puts a 'backspin' on the BB allowing it to briefly counteract the effects of gravity meaning it can fly straight for a longer distance.

    Another method would be to upgrade your Airsoft's barrel to a tighter bore as this gives it more pressure from behind and forces it out of the barrel on a straighter path.
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  11. #10  
    Moderator Moderator AlexP's Avatar
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    Thanks for the replies everyone, I got some good answers. Keep the thoughts coming though, if anyone has any more.
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