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Wind Calculations Brain Teaser

 
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  #1  
Old 03-20-2008, 07:31 AM
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Wind Calculations Brain Teaser

Alright guys, I need some help! I am trying to come up the a scaled down version of my hunting cartridge for practice. I'm in NC, so I don't have lots of long ranges with which to practice. I was feeding numbers into my ballistics calculator, and it is not telling me what I want to hear. If the flight time of two rounds is the same, and the BC is as well, would not the wind movement be also? What am I missing?

Thanks,
Shane
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  #2  
Old 03-20-2008, 07:49 AM
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IMO, no, but I have been wrong before

A .22 and a .511 bullet with the same BC certainly have a far different profile in the wind, and I would think that the 50 cal would be pushed further.

edge.
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  #3  
Old 03-20-2008, 12:58 PM
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I used Exbal with 2 different bullets. One at 100 grains and one at 400 grains and both with a BC of .300 and both launched at the same muzzle velocity. All weather factors are set at the same values.

If you use ballistic software you will find that if you have a 100 grain bullet with a BC of.300 and a 400 grain bullet with a BC of .300, for the time of flight to be the same the muzzle velocity would have to be the same and this isn't likely to happen although it's theoretically possible.;)

All ballistic factors would be the same at all yardage intervals with the exception of energy. The advantage goes to the heavier bullet in the energy department.

The answer to your question is a theoretical Yes.;)

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Old 03-20-2008, 07:34 PM
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Thanks guys, just want to clarify something, and get you to weight in again. I'm using 155gr. A-Max. for long range. I want to develop a short range load that will just be a scaled down version (same bullet) of the long range version. One load is around 3000fps, and the other is around 1400fps. The flight time is the same, the weight is the same, the B.C. is the same (Well closely since B.C. of a bullet is dependent on velocity), shouldn't the effect of the wind on the two bullets be the same?

Bullet 1 with flight time A being pushed by wind B should = X

Where Bullet 1 = Bullet 2 then,

Bullet 2 with flight time A being pushed by wind B should = X


Is this not right?

Thanks,
Shane
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  #5  
Old 03-20-2008, 07:43 PM
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If one has a velocity of 3000 fps and the other has a velocity of 1400 fps then how can they possibly travel from point A to point B in the exact same amount of time???:confused:

With that much velocity difference the time of flight is going to be quite large.;)

If you're talking about the time of flight dictating the distance traveled at the different speeds then the effect of the wind would probably be the same, it's just that the distance traveled by each, at different speeds, is going to be far different.

See below. I didn't look up the BC, I just put a value in. The end result still displays what happens.

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Last edited by ss7mm; 03-20-2008 at 07:50 PM.
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  #6  
Old 03-20-2008, 10:14 PM
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I think that a bullets BC is based on velocity. This may be very important if you are going to launch it at 1400 fps since you run the risk of going transonic.

edge.
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  #7  
Old 03-21-2008, 02:37 PM
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Yes, to both of you. Thanks for your input. I am shooting the 1400fps round a close range (100-200yrds). The 3000fps is for Intermediate Range (300-600yrds). The flight time is will be very close, and so will bullet path. I just could get my ballistics software to agree with me about wind. Below is what I should have posted first, but I was frustrated and not thinking straight. Thank you both for your assistance. I'm much calmer now, and can think more clearly. I don't have enough patients for inanimate objects (computers).

Thanks Guys,
Shane

Notes:
IR Load; 155gr. Hornady A-Max with 0.435 BC, MV @ 3000fps, Zeroed at 200.

Practice Load; 155gr. Hornady A-Max with 0.435 BC, MV @ 1400fps, Zeroed at 77 (I think).
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