Thread: Wind in the Mountains

Originally Posted by el borracho

R93 same BC ,same velocity why wouldnt they stay the same?

Physics.


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Originally Posted by kimjon

For my on interest I had a play on a Ballistic programme, I entered in some numbers purely to generate some info to compare my thoughts on bullet weight playing no role in beating the wind.

I used these figures for below:

Using a 300grain 0.338 bullet with a BC of 0.66 and a velocity of 2820fps

1000-215.8-20.621.52.12268.92.084571.41.18600



And this time using a 160grain .284 bullet with a BC of 0.66 and a velocity of 2820fps

1000-215.8-20.621.52.12268.92.081828.61.18600


Both exactly the same, bar the energy figures. Velocity, drop, drift etc are all the same, so from my reckoning bullet weight has nothing to add as far as beating the wind goes, its simply comes down to BC & velocity (time in flight).


kj

My shooter program must be fucked. I got an moa difference over 700 yrds between a 130 and 160 gr .264 All I Changed was weight.
The heavier pill will maintain velocity better than a lighter pill. Therefore there must be a difference somewhere no???


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Your doing something wrong R93. The only difference is downrange energy. If they've got the same BC they'll follow the same trajectory. Ballistic FTE just confirmed it for me.

Your obviously limited to G1 bc. Worthless beyond approx 500.
I didnt do anything wrong. I changed the weight only.
Doesnt matter as it would not happen in real the world anyway.
To many variables too mention.


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I used the G7 drag model. Maybe you'll trust these guys: exterior ballistics

From that page:

Relationships between Different Bullets with the Same Ballistic Coefficient

Suppose that two bullets of different weight or different caliber have the same ballistic coefficient; how do the ballistics of the two bullets compare?

To start with, assume that the two bullets are fired with the same muzzle velocity. This gives a common basis for a generalized comparison. Since the bullets have equal C’s , they have equal drag decelerations, and they slow down equally fast. Consequently, if the two bullets start with equal muzzle velocities, at any range they will have equal velocities, equal times of flight, and equal drops. Unless they have equal weights, they will have different energies, however. Since energy is proportional to weight, the heavier bullet will have proportionately more energy at any range.

Originally Posted by R93

Physics.


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physics is correct -different weight but ''same drag'' and same speed means they go to the same point and arrive at same time

I accept in theory they should match.
But its just that theory. No one has been able to prove it by firing.
Again my ballistic calc must be fucked as it shows a difference at ranges beyond 700.

Edit: No it doesnt, it required a decimal input that I missed. Apologies everyone, It is the same, in azimuth and elevation


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Some people will argue anything rather than admit they're wrong

Dude, sort your calc before doing too much LR.

No worries. I will.
I happy to admit I am wrong, anytime, as I have in this thread. I am sure most people in this place would agree I take the piss out of myself more than anything.
I dont get off on proving or thinking I have proved someone is wrong about anything. You obviously do. In this instance however, can you provide a real world example to prove your right?


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Send me some projectiles with the same BCs in 7mm and 30 cal and I'll happily load some up and do it if you need that. Personally I'm not getting off on it, just pointing out what is obvious to anyone who cares to accept logic (in addition to external ballistics and simple science). Lets leave it be shall we

Why do you have to be so insulting?
Does it make you feel superior in some way?
If I am wrong so be it. I am wrong.
It happens.



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LOL, dude, I'm not being insulting. Catch ya later

Wrong again...... bugger! Condescending perhaps? If it was so obvious, simple and logical, as you put it, it is amusing you needed to confirm it on your ballistic calc.



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we all get to share in the pie at some stage R93 ,it aint exclusive -an i f-n hate humble pie

Originally Posted by el borracho

we all get to share in the pie at some stage R93 ,it aint exclusive -an i f-n hate humble pie

I eat my fair share of it El B.
Especially where the cook is concerned. I get it force fed.


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