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Thread: Why do my bullets just disappear?

  1. #1 Why do my bullets just disappear? 
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    I don't know how all those warships hit targets from so far away. Whenever I try, my bullet just despawns after 500 meters, even with my most powerful sniper rifle. How do I get around this problem? Thanks for the help?


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    Genius Duck Moderator Dywyddyr's Avatar
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    Moved to General discussion - this isn't a military technology question.
    There are also a number of problems with the question as posed:
    what do warships have to do with it? (Given you also talk about a "sniper rifle" and "bullets").
    you haven't specified which game you're talking about.


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    Quote Originally Posted by Dywyddyr View Post
    Moved to General discussion - this isn't a military technology question.
    There are also a number of problems with the question as posed:
    what do warships have to do with it? (Given you also talk about a "sniper rifle" and "bullets").
    you haven't specified which game you're talking about.
    Sorry I misclicked! I wasconfused by the name of the the subforum. I am talking about not a game but real life. The warship thing was a mistake. My bullets burn up or "despawn" in real life after a while of shooting. (I tested it)
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    Genius Duck Moderator Dywyddyr's Avatar
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    Unless they're old (or badly manufactured) bullets1 then I'd suggest that it's not happening.

    1 In which case it could be "blue flash" - they break up due to stress caused by spin: although why that should occur at 500m rather than shortly after leaving the muzzle I'm at a loss to say. Nor does the "after a while of shooting" make sense.
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    Quote Originally Posted by imgeniusurn0t View Post
    Sorry I misclicked! I wasconfused by the name of the the subforum. I am talking about not a game but real life. The warship thing was a mistake. My bullets burn up or "despawn" in real life after a while of shooting. (I tested it)
    They don't burn up and they don't "despawn." They may well fragment - but if you found all the pieces you'd have the mass of the original bullet.
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    Quote Originally Posted by imgeniusurn0t View Post
    I don't know how all those warships hit targets from so far away. Whenever I try, my bullet just despawns after 500 meters, even with my most powerful sniper rifle. How do I get around this problem? Thanks for the help?
    The longest recorded kill by a sniper is over a range greater than 3500 meters or over 7 times your 500 meter figure.

    As far as the range of big guns on ships vs a rifle goes, this is a matter of the size of the projectile. A big gun might have a muzzle velocity of 820 m/sec and a range of 39 km. This is not that much greater than the 805 m/sec muzzle velocity of the rifle used above. The rifle however, has a much shorter range. The ship gun fires a much larger projectile. As a result, the square-cube law comes into play. If you increase the dimensions of an object by a given factor, you increase its surface area by that factor squared and its volume by that factor cubed. So as objects get larger there volume increases faster than their surface area. The overall mass of the object is related to its volume. Thus a small rifle bullet is going to have a much smaller mass to surface area ratio than a ship gun projectile. Air drag is related to surface area and the objects inertia is related to its mass. So air resistance is more effective at slowing down a rifle bullet than it is at slowing down the ship gun projectile. The rate at which a rifle bullet loses speed after leaving the barrel is much faster than the rate at which the ship projectile will, giving the ship gun a longer range.
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    Forum Professor Dave Wilson's Avatar
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    Fascinating post, I had forgotten all about the square-cube law, going to look it up on Wiki.
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    Quote Originally Posted by Janus View Post
    Quote Originally Posted by imgeniusurn0t View Post
    I don't know how all those warships hit targets from so far away. Whenever I try, my bullet just despawns after 500 meters, even with my most powerful sniper rifle. How do I get around this problem? Thanks for the help?
    The longest recorded kill by a sniper is over a range greater than 3500 meters or over 7 times your 500 meter figure.

    As far as the range of big guns on ships vs a rifle goes, this is a matter of the size of the projectile. A big gun might have a muzzle velocity of 820 m/sec and a range of 39 km. This is not that much greater than the 805 m/sec muzzle velocity of the rifle used above. The rifle however, has a much shorter range. The ship gun fires a much larger projectile. As a result, the square-cube law comes into play. If you increase the dimensions of an object by a given factor, you increase its surface area by that factor squared and its volume by that factor cubed. So as objects get larger there volume increases faster than their surface area. The overall mass of the object is related to its volume. Thus a small rifle bullet is going to have a much smaller mass to surface area ratio than a ship gun projectile. Air drag is related to surface area and the objects inertia is related to its mass. So air resistance is more effective at slowing down a rifle bullet than it is at slowing down the ship gun projectile. The rate at which a rifle bullet loses speed after leaving the barrel is much faster than the rate at which the ship projectile will, giving the ship gun a longer range.
    Ok. Let me see if I got this straight. Because the take-off velocity is virtually the same for both, then more mass is a boon to distance, while more surface area, as usual, is a deterrent to it. Therefore as the projectile increases in size, the “boon factor” increases at a greater rate than the “deterrent factor”.


    Is this a decent “in a nutshell”?
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    Genius Duck Moderator Dywyddyr's Avatar
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    Quote Originally Posted by Vexspits View Post
    Ok. Let me see if I got this straight. Because the take-off velocity is virtually the same for both, then more mass is a boon to distance, while more surface area, as usual, is a deterrent to it. Therefore as the projectile increases in size, the “boon factor” increases at a greater rate than the “deterrent factor”.


    Is this a decent “in a nutshell”?
    More or less.
    As Janus pointed out, increasing calibre raises the area by x2 and the mass by (roughlyA) x3 for rounds made of the same materials.
    What counts (in the mass vs surface area question) is the areal density (mass per unit cross-sectional area), oh and drag factor which includes shapeB. In other words a small-area very low density round would lose more velocity (per unit distance) than a high mass high area one.

    A Mass can be increased without a concomitant area increase simply by making the round longer. (But then you run into flight stability problems once the length exceeds about 5 x the diameter - hence fin-stabilisation for long rod penetrators from tank guns).
    B Bullets generally have a boat tail while larger calibre rounds (artillery/ ships' guns) tend(ed) to have a flatter base (with concomitant higher drag): it all gets a bit fiddly and complicatedC.
    C To the extent that true drag factors are measured (using fairly technical equipment and ranges) rather than being calculable.
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    Have done some more research, and things are even more complicated than I thought. I came across the German mathematician and aerodynamicist Wolfgang Haack. I most certainly do not understand all the maths, but it is very interesting.
    " Haack shapes or Sears–Haack bodies are not ogives or constructed from any other geometric figures. The shapes are instead mathematically derived streamlined bodies of revolution for the purpose of minimizing drag. Minimal projectile-shape variations can change the air-resistance and hence the effective range of high powered gun projectiles considerably, especially when they change velocity from the supersonic to the transonic and eventually to subsonic air flow regimes or vice versa during flight. For this kind of applications the Haack shape offers significantly improved characteristics compared to the tangent ogive or even the secant ogive often used for very-low-drag bullets and artillery shells.[3] Only after the end of World War II have Haack shaped projectiles for artillery guns and sniper rifles been produced. "

    https://en.wikipedia.org/wiki/Wolfgang_Haack
    Last edited by Dave Wilson; March 19th, 2019 at 09:36 AM. Reason: missed out a word
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