Bucking wind vrs BC

[ROVERT]

How does adding length make the bullet more slippery!

Adding length adds mass without adding diameter. Mass is on the top of the B.C. equation and diameter is on the bottom. If you can increase the top of the equation without increasing the bottom, the value for B.C. becomes larger more quickly than by simply increasing the scale. For example, a 200 gr. .308" bullet has a higher B.C. than a 200 gr. .338" bullet, given the same basic form.

 

[usmc 89]

This is interesting but what is the employable point to all of this

 

[ROVERT]

This is interesting but what is the employable point to all of this

I was trying trying to answer a question as to whether or not B.C. and muzzle velocity were the only important factors in resisting wind deflection or if mass played some additional role in a bullets ability to do this. It kind of snowballed from there.

I guess the most important thing that can be taken from this is something most of us are well aware of and that is that a bullet with a high B.C. fired at a somewhat slower velocity can cope with the wind better than lower B.C., higher velocity bullet.

I think what is confusing a lot of people is that, despite having a longer total flight time, the higher B.C. bullet can still be less affected by wind. While the total flight time is longer the component of that flight time for which wind can act on the bullet is actually less (lag time). People look at just the total flight time numbers and assume that something like mass or momentum must also be contributing to "bucking the wind" while it is not. The role of mass in resisting wind deflection is taken into account by the ballistic coefficient. It does not provide some sort of secondary advantage while the bullet is in flight.

This is not hugely useful except in choosing a bullet or cartridge which will most effectively resist wind deflection.

 

[usmc 89]

You did a good job on presenting your information. Have you begun shooting matches yet?

 

[Desert Fox]

This is interesting but what is the employable point to all of this

They'll find out as soon as they send the first one out to yonder.

 

[Oldtrader3]

DF, that is why I said verify empirical data! Having been an engineer for 40+ years, I have watched empirical calculations that people nearly staked their careers on, go south when actually tested under real life conditions. Too many variables make calculation accuracy inversely reliable to the number of dependant variables involved (Charlie's Law).

 

[Desert Fox]

DF, that is why I said verify empirical data! Having been an engineer for 40+ years, I have watched empirical calculations that people nearly staked their careers on, go south when actually tested under real life conditions. Too many variables make calculation accuracy inversely reliable to the number of dependant variables involved (Charlie's Law).

So true, especially in the science of Ballistics.

 

[nvbroncrider]

DF, that is why I said verify empirical data! Having been an engineer for 40+ years, I have watched empirical calculations that people nearly staked their careers on, go south when actually tested under real life conditions. Too many variables make calculation accuracy inversely reliable to the number of dependant variables involved (Charlie's Law).

Thought that was Murphy's? What can do wrong will!

 

[usmc 89]

This is interesting but what is the employable point to all of this

They'll find out as soon as they send the first one out to yonder.

True, I remember when I went to my first precision rifle match a few years ago I had charts that were proofed and figured I would do well. I got destroyed I think I shot a 31 out of 68 targets. Bottom line is this in my opinion, you can have all the correct ballistic values in the world but they are only as accurate as ones ability to interpret the condition and correct for it this also compounded without the use of sighting shots and wind flags. I always smile when guys are posting about which rifle is good for coyotes out to six hundred yards. Most rifles are capable of doing that the problem is there are few guys operating that rifle that are capable of doing so even with a 105 amax. "sorry but I had to". Nice work on your last match SF.

 

[SJB358]

few guys operating that rifle that are capable of doing so even with a 105 amax. "sorry but I had to"

Don't worry Jeff! I laughed my butt off! That cracked me up, well played sir, well played! :lol:

I am with all of you. There are much better rifle shooters that hang targets around here. That is why I hang around here, hoping you all rub off on me. I learn slowly and the hard way.. It gets done, but I like to hear of tips that will accelerate the learning curve!

 

[usmc 89]

Thanks Scott hoping you will stop by on your way to Idaho? And that last post was meant to say DF not SF.

 

[Desert Fox]

This is interesting but what is the employable point to all of this

They'll find out as soon as they send the first one out to yonder.

True, I remember when I went to my first precision rifle match a few years ago I had charts that were proofed and figured I would do well. I got destroyed I think I shot a 31 out of 68 targets. Bottom line is this in my opinion, you can have all the correct ballistic values in the world but they are only as accurate as ones ability to interpret the condition and correct for it this also compounded without the use of sighting shots and wind flags. I always smile when guys are posting about which rifle is good for coyotes out to six hundred yards. Most rifles are capable of doing that the problem is there are few guys operating that rifle that are capable of doing so even with a 105 amax. "sorry but I had to". Nice work on your last match SF.

Yup! Same here.

My first 1K competition, I had all my stuff laid out, PDA, Kestrel, LRF, spotter, the whole nine yards. I thought I was ready. As soon as the target was raised, panic sets in. The distance was so intimidating that my nerve is doing number on me. To top it off, my Kestrel was telling me wind direction and speed, but the flag at the halfway point is being blown opposite the flag at the 1K marker. At this point, all I can do is hope that my first shot will stay on paper. I did not do too well that day but I did not do too bad either. But I learned something that day. You can have all the latest electronic gadgetry and read every book there is about ballistics and shooting. But at the end of the day, it all boils down to you and your ability to outwit the elements.

And yeah, my second time competing, I place Third.

 

[usmc 89]

True, it all looks good on paper but if that's all you have for experience a humbling is eminent.

 

[onesonek]

DF, that is why I said verify empirical data! Having been an engineer for 40+ years, I have watched empirical calculations that people nearly staked their careers on, go south when actually tested under real life conditions. Too many variables make calculation accuracy inversely reliable to the number of dependant variables involved (Charlie's Law).

Thought that was Murphy's? What can do wrong will!

Charlie and Murphy are related :wink:

 

[Oldtrader3]

At my age and mental condition, I probably am!

 

[onesonek]

At my age and mental condition, I probably am!

That could very easily be phrased with the substitutions of experience and wisdom Charlie!

 

[Oldtrader3]

Nobody in the letters that I write to the local newspaper ever accuse me of that, even when I correct their fractured, Liberal histrionics which they think is real history!