At what altitude will a bullet go twice as far?

TXAZ

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  • Oct 3, 2020
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    Realizing drag drops as air density decreases, is there an altitude where a bullet will go twice as far, compared to sea level?
    The main assumption is the target is at elevation as the shooter.
    Any recommendations on how to calculate appreciated.
     
    1) A standard shoulder fired rifle bullet, fired at sea level is unable to achieve an elevation that reduces atmospheric pressure significantly enough to noticeably reduce air friction (drag) on the bullet.
    2) Without the effects of air friction, negating a bunch of other factors, the optimal angle of fire is 45 degrees.
    3) In real life, that optimal angle, depending on air temperature, azimuth of fire, position on earth, just to name a few variables, is more near 41 degrees.
     
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    With maxing out JBM ballistics on both high and low environmentals, I’m getting close at a theoretical 44k feet.

    Now this was using a -4000ft and 40.00 pressure on the bottom for an equivalent -14,000ft up to 15,000 with a 15.00 pressure with an approximate 30,000 DA.

    Now the atmosphere isn’t linear so starting that low is unrealistic and the air thins faster the further you climb so let’s just say, it’s above anywhere you could actually shoot.

    Fun exercise though.
     
    I live and shoot at 4650' elevation give or take a foot or two and that really doesn't net you a whole lot compared to sea level.
    There is a difference obviously depending on temp and humidity based on altitude but the is no golden height above sea level like you asked unless you are shooting near verticle from a helicopter.
    Maybe next time I'm up on the Mesa I will do some accross canyon shooting at 10,400' and compare that to my normal dope.
     
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    Fun thought exercise, but your terms aren't clearly defined as to whether you're looking at ballistics or "mortar fire for distance". For giggles I ran a couple possible ballistic scenarios (using a Berger 105 hybrid at 2850fps).

    If you are shooting at sea level, with the barrel dead level to the ground and not dialing for elevation, from a shooting bench that's 36" high, the bullet goes about 455 yards before it hits the ground. At 15,000 feet elevation that bullet travels only 20 yards farther... about 475 yards.

    Looking at ballistics where you would dial for elevation, assuming the practical maximum effective range of a bullet as being >Mach 1.0, then you could compare the following:

    1) Sea level, Zero degrees F temperature, 30.9 in/hg = Max effective range of 1155 yards.
    2) 15,000ft elevation, 80 degrees F, 29.0 in/hg = Max effective range of 2310 yards.

    So it would take starting at a freezing high pressure day at sea level then going to a hot low pressure day at 15k feet elevation to "double" the effective range of a rifle.
     
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    1) A standard shoulder fired rifle bullet, fired at sea level is unable to achieve an elevation that reduces atmospheric pressure significantly enough to noticeably reduce air friction (drag) on the bullet.
    2) Without the effects of air friction, negating a bunch of other factors, the optimal angle of fire is 45 degrees.
    3) In real life, that optimal angle, depending on air temperature, azimuth of fire, position on earth, just to name a few variables, is more near 41 degrees.
    41. I always wanted a number for this, I know I'm not the first lol. Better than researching high atmosphere orbital dynamics.



    It's supposed be 42 goddammit. I've been waiting millions of fucking years for you to fuck it up.
     
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    Reactions: Modoc and Aftermath
    41. I always wanted a number for this, I know I'm not the first lol. Better than researching high atmosphere orbital dynamics.



    It's supposed be 42 goddammit. I've been waiting millions of fucking years for you to fuck it up.
    It's right in there and if you wait for the right day with the wind at your back and the temperature is just right and you are shooting the right direction in relation to earths rotation....it might be 42....or it might be 40.

    EDIT: there really must be some artillery guys here that have the little cardboard calculators that can do this for you in a hurry. I know there must also be some website or phone app that can also figure it rapidly/
     
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    It's right in there and if you wait for the right day with the wind at your back and the temperature is just right and you are shooting the right direction in relation to earths rotation....it might be 42....or it might be 40.

    EDIT: there really must be some artillery guys here that have the little cardboard calculators that can do this for you in a hurry. I know there must also be some website or phone app that can also figure it rapidly/
    I'll have you know that every shot I ever fired was directed at that bastard at the core of the planet.
     
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